To understand the scope and scale of that transformation, it’s worth looking at what the “subway-streetcar network” looked like immediately before that transformation. One might think that that would be a simple task: simply Google 1921 BERy map boston and this is the first result:
Except… this map doesn’t tell the whole story. A little bit of further digging reveals that many of the surface lines on this map didn’t actually operate into the subway – the far-flung lines in West Roxbury, for example. Moreover, this map omits the foreign cars that weren’t run by the Boston Elevated Railway but still operated into the subway, turning at the Brattle Loop.
Finding the “subway-streetcar routes”
Identifying which routes operated into the subway 101 years ago is actually not a simple task. Again, I believe this is a consequence of how BERy saw the Tremont Street Subway: it wasn’t a rapid transit line and it wasn’t a “trunk” of the network – it was just a way to get streetcars off of congested streets in downtown. From what I’ve seen, it probably never would have even occurred to BERy officials to publish a map of the “subway-streetcar network” – they were all just “surface lines”.
Making matters more difficult is that BERy also did not (to my knowledge) publish public timetables for specific routes. There were internal timetables, though my understanding is that they were very internal indeed, and are difficult to parse a century later. Most notifications of changes in routes, for example, appear to have occurred in newspaper announcements.
Here I am indebted to the labors of love of numerous local transit historians. Building on their work, I have created what I believe is the first map of its kind: a full diagram of all BERy services that offered one-seat rides into the downtown subways in 1921.
Applying the anachronistic visual language of today’s Green Line and Blue Line, I’ve framed the 1921 network with modern points-of-reference, to make it easier to understand its scope and complexity.
Again, it’s important to understand that this diagram does not represent how BERy officials or riders would have conceptualized their system. However, thinking of the streetcar network in these terms is also vital for understanding the decline of Boston’s streetcar network (which began much earlier than we often think of it as.)
List of Routes
The routes operating into the subways included the following (note that many routes had short-turn turnbacks, the same way some trains on today’s E Line terminate at Brigham Circle); I have included some modern comparisons based on today’s routes in parentheses:
Kenmore Portal lines
Lake Street [Boston College] via Commonwealth Ave (B)
Reservoir [Cleveland Circle] via Beacon Street (C)
Ipswich Street lines
Chestnut Hill and the Cypress St Carhouse (55 + 60)
Huntington Ave lines
Lake Street [Boston College] via Village Sq [Brookline Village] (E + 65)
Jamaica Plain Carhouse (just south of Jamaica St) (E + 39, but not all the way to Arborway/Forest Hills)
Pleasant St Portal lines
Dudley [Nubian] (similar to SL5, but on Dover St [East Berkeley St] from Washington to Tremont)
City Point (9)
East Boston lines
Central Square, Cambridge via Joy St Portal (no equivalent, but somewhat similar to the proposed Blue-Red Connector)
Jefferies Point (120)
East Boston and Chelsea (114/116/117, 112, and 121)
Orient Heights (120)
Revere Beach (paralleling the route of today’s Blue Line on Bennington St and Ocean Ave)
Davis, and Clarendon Hill, via Somerville Ave or Highland Ave (87 and 88)
Canal Street Incline lines
Sullivan via Main St (92)
Sullivan via Bunker Hill (93)
Beachmont (using part of today’s 119)
Revere Beach (116 and 117)
Lynn (probably most similar to today’s 455)
Salem and the North Shore (450)
Melrose Highlands via Malden & Chelsea (I believe roughly using today’s 131 north of Malden Center)
This has been a gargantuan project, far more perhaps than the map itself would suggest. The details needed to pinpoint the system exactly as it existed in 1921 are numerous and scattered. As in my previous post, I must heartily thank the army of transit historians who have come before me, including Ron Newman, Bradley Clarke, O.R. Cummings, Frank Cheney, and Anthony Sammarco.
I want to extend a special thanks to DAS, who has expertly collated the primary source material upon much of this map is based, enabling us to expand, contextualize, and occasionally correct the work done by Newman, Clarke, Cummings, Cheney, Sammarco, and others. His expert review caught many errors of mine, answered numerous arcane questions of mine, and uncovered the fine details at the margins of this project to ensure this map was as accurate as possible.
When I was a child, reading the copy of Trolleys Under The Hub my parents had given me, my imagination was enchanted by the idea of a “Green Line” that apparently had so many branches. This is the map that I had wanted to see then, so it is a profound delight to finally see it brought to life; as such, I offer my profound thanks to all those who helped me create it.
Notes and Further Reading
As printed in the image:
Services on this map operated into the Tremont Street Subway and the East Boston Tunnel in 1921.
Street names included here are illustrative and not exhaustive; some routes used additional streets not marked.
Additional transfer points existed but are not shown here.
Huntington and Ipswich services ran at street level along Boylston, paralleling the subway below.
Additional surface-only services ran over shared stretches of track, but are not marked here (for example, an Allston-Dudley service that ran through Village Square).
Services intermingled in the Central Subway, and sometimes were through-routed on to new routes once exiting the subway as needed.
Occasional additional suburban services may have been through-routed in the subway (for example, from Arlington), but these services appear to have been irregular.
Some foreign transfers may have been available at additional locations than are marked here (e.g. Watertown, which likely almost certainly had transfers to the Middlesex & Boston Street Railway).
Tracking down which routes were running into the subway in 1921 was surprisingly difficult. When possible, I’ve used primary sources, but in some cases have relied on secondary sources, particularly since some transit historians have obtained access to archive materials that are more difficult to access remotely or as a member of the public.
I did a poor job of cataloguing my references when building this map. As such, I am currently in the process of rebuilding the reference list for this post. My WIP reference list is available as an appendix to this post.
Everything old is new again. The T is, once again, shuttering significant parts of its network this summer, in order to accommodate maintenance and construction. The Red Line is seeing a string of late evening closures, while the Green Line is seeing much longer shutdowns — including over 40 days of closure on the Union Square branch.
Naturally, I have made some maps.
(I didn’t want to sink too much time into this project, so the maps below are not free from imperfection.)
During this period, the Union Sq shutdown will overlap with a bustitution of the B Line.
The T will apparently not be providing a shuttle for the Union Sq branch, instead directing riders to local bus routes with transfers at Lechmere and East Somerville. I’ve tried to illustrate those here. Alas, it is a bit cramped.
Phase 2: July 29 – August 9
Following the resumption of service on the B Line, a complete shutdown of service between North Station and Government Center will be instituted to accommodate demolition work on the Government Center Garage. It appears that no shuttle will be provided, and the T’s advice is simply to walk from one station to the other.
Phase 3: August 10 – August 28
During these two-and-a-half weeks, the core segment will be restored and the only ongoing long-term disruption will be the unshuttled closure of the Union Sq branch.
To be clear, this is a proof of concept; there are a number of small details that need correcting, and while I think the overall concept works, there are some clear areas for improvement in a subsequent revision. But, I think it does prove out the concept.
The current diagram draws clear lineage to the Cambridge Seven Associates’ original diagram (which captured my imagination as a child with its simplicity and elegance, particularly when it looked more like this). Today’s diagram is much more complicated than the original, due to the need to add additional information, including
Explicit markers for all stops on the Riverside Line
Explicit labels for all stops on the B, C, E, and Mattapan Lines
The Silver Line
Commuter rail stops (particularly along the Fairmount Line)
Key bus routes
Plus the editorial decision to include the geographic markers of the shoreline.
That last point reveals a fundamental difference between the original and current diagrams: the original made zero effort to appear geographically accurate, while the current makes some effort to hint at accurate geography… in some places.
The right half of the map – the South Shore, South Boston, the Shawmut Peninsula (a.k.a. Downtown), Charlestown, East Boston, and the communities along the Mystic River – is vaguely accurate, albeit somewhat compressed.
The left half, by contrast, is much more diagrammatic: straightening and simultaneously stretching & compressing the four branches of the Green Line, straightening and simplifying the Red Line and Key Bus Routes, while maintaining some suggestion of a geographically accurate Charles River.
Kenneth Dumas, the designer of the current diagram (and its previous iterations going back to 2000 when the shift was made away from a purely non-geographic diagram), has spoken about the process by which we arrived at today’s diagram; it’s a fascinating watch that I highly recommend if you enjoy transit maps. Suffice it to say, the current diagram represents an effort to harmonize the desires of a wide range of stakeholders.
I have long wanted to design a diagram for the T that includes the following:
Key bus routes, shown as cleanly as possible and designed into the map from the start
All stops on the Green Line branches
(I actually have not particularly wanted to list out all of the surface stops on the B/C/E Lines, but my understanding is that there is user research showing clear preference for their inclusion)
Walking transfers, including
State – Downtown Crossing,
Copley – Back Bay,
Symphony – Mass Ave,
Brookline Village – Riverway, and
Reservoir – Cleveland Circle
All stops on the Fairmount Line (future-proofed for its eventual conversion to near-rapid transit standards)
The design concept: geographically accurate inner zone & diagrammatic outer zone
Achieving my goals, while maintaining the information on the current diagram, posed several challenges. But as I thought about it further, I realized that several of the thornier issues could all be solved by a highly-geographically accurate diagram, including:
the Silver Line, and
to a lesser extent, baking the key bus routes harmoniously into the design of the map
The physical paths of the Green and Orange Lines themselves provided a design to show the walking transfers; this was a key revelation for me: use the physical paths as the starting point for the design, rather than abstract ideas such as “I want the Orange Line to be as straight as possible and form a perfect right angle with a Red Line that is also as straight as possible” (see for example Michael Kvrivishvili’s original design).
But, I wondered: was the use of the “To” box really that different from the current diagram’s treatment of the B/C/D/E Lines (and to a lesser extent the Blue Line and Braintree Line)?
There’s very little geographic information being conveyed on those outer lines; there are few or no transfers being shown; there are few or no eye-catching bends that might provide implicit visual cues. Especially on the Green Line branches, the current diagram really just uses a list of stations, along a colored line with white dots.
So, I wondered, what would happen if we had a diagram with a geographically accurate inner section and a maximally diagrammatic outer section?
Hence, the map above.
Notes on the map
A few things to draw attention to:
This design uses the original map’s labels and other elements at their original size relative to the page. If printed on a piece of paper the same size as the current map, all of the labels (along with the widths of the subway and bus lines) should be the same size. I know there are ADA guidelines around things like sizing and visual contrast; by reusing as much of the original map’s design language as possible, I’m hoping to generally satisfy those requirements, even if I’m unfamiliar with them.
Alignment for bus routes
Stations are aligned so that connecting bus routes (in this design, the highest frequency “all-day-15-min” routes from the Bus Network Redesign) are maximally straight. These include:
Non-geographic diagram in outer zone
Outside of the “inner zone”, the geographic fidelity of the diagram drops so severely that there’s no way it can be interpreted as being anything other than what it is: a list of stations. This is reinforced by the disappearance of the bus routes and the coastline, and the addition of the “transfer labels” at each station. An earlier version of the diagram featured an explicit “box” delineating the inner vs outer zone; this became unwieldy, however, especially when dealing with the Green Line branches, so I opted instead for an implicit transition.
Color-coded bus routes
Instead of using the current diagram’s “light brown” for the Key Bus Routes, or the official brand guidelines’ “Brand Bus Yellow”, the bus routes have been color-coded based on the hub they operate into. This is far from a perfect system, and in some cases I had to make arbitrary choices. (For example, the T7 and many of the routes running through Roxbury Crossing are colored based on running through State St and Roxbury Crossing respectively, e.g. major transfer points the route travels through rather than to.) Still, I think it is a useful way to differentiate the routes, and somewhat inadvertently highlights the new connectivity of the redesigned routes (e.g. the T28 being a Green route, or the T110 connecting Wonderland to the Orange Line).
With today’s timetables, the Fairmount Line should not appear on the map using equal visual language to the rapid transit lines. However, increasing frequencies to “turn-up-and-go” levels should be a major priority for the T and the City, and I wanted this diagram to be future-proofed to enable that.
Silver Line, simplified
The Bus Network Redesign has given us would-be transit map designers a godsend: the elimination of the SL4/SL5 reverse branching & loops. Now we have a simple dog-leg that slots nicely alongside the Orange and Red Lines. The only hiccup is (as I interpret the Remix map), Chinatown will receive northbound service only. I have opted to subtly mark this using a directional triangular for the stop, instead of a circle, and excluding a Silver-Orange transfer indicator at Chinatown (compare to Tufts Medical Center). On a “real” version of this map, the Chinatown label would probably get an asterisk with a note in the legend to the effect of, Silver Line stops at Chinatown going northbound only.
Park St, Winter, Summer, and Washington
This probably falls under the heading of “too clever by half”, but I’m still pleased with it. In general, this map does not mark transfers particularly explicitly. I experimented using black circles, or black dots within circles, but the black circles created contrast problems and the black dots were too subtle.
Instead, the indication of transfers is derived from the physical positions of the stops. For example, the Blue-Green transfer at Government Center is indicated by the Blue and Green Lines sharing a stop indicator. As it happens, only two transfers are marked in this manner: Park St and Government Center.
The rest are marked using transfer bars to connect visually distinct stops. In some cases, the visual distance is a design artifact: for example, the Green-Orange transfer at North Station or the SL1/2/3-Red transfer at South Station are in reality basically as proximate as, e.g., the Red-Green transfer at Park St.
But one benefit is that two of the more complicated transfers are visualized accurately: State, and Park/Downtown Crossing.
The transfer between the Blue Line and the southbound Orange Line (the platform formerly known as “Milk” after the cross-street above) is, I believe, the longest in-station transfer on the system. From the western end of the Blue Line platforms to the northern end of the Milk Street platform (I believe under the intersection with School St) is about 800 feet, as I estimate. By comparison, the Green-Orange transfer via the Winter Street Concourse is about 550 feet.
All things being equal, I don’t see a particular need to visually indicate this lengthy transfer distance. However, I chose to add it because I wanted to implicitly indicate that the T7 transfer (on Congress St) is more proximate to the Blue Line than to the Orange Line. So I wanted to separate out the Blue Line station from the Orange Line.
So, I wanted to indicate on the map that Downtown Crossing will provide a good Silver-Red transfer but subtly suggest that Silver-Orange transfers are better taken at Tufts Medical Center. By separating out the Red Line station (nee “Washington”) from the Orange Line stations (“Winter” and “Summer”), the diagram is able to show exactly that. Again, in this case the physical layout of the network in the real-world has provided the needed design specification.
There are two sets of problems with my diagram: some problems are execution-related and presumably could be remedied by the touch of a professional; others are conceptual and endemic to the idea of the map itself. Of the drawbacks listed below, I’m not sure which are execution-related and therefore “salvageable”, but I’ll make some guesses.
Busy margins and excess inner blank space
This one I think is execution-related and could be ameliorated by some mild tweaking. This diagram is very busy at the margins overall. To a certain extent, this is by design: I always knew that the outer regions of the diagram were going to be busy with station lists. However, I think the “inner map” section could be compressed by maybe 20%, and free up much needed space, especially at the bottom of the diagram. (For example, there really doesn’t need to be that much space between stops on the Southwest Corridor; the SL4/5 stops probably are the limiting factor here, but they too definitely could be closer together.)
Likewise, I think the “inner map” could also be further compressed along the “Red Line axis”, particularly in the northeast corner. Harvard and Central could both be moved in closer to the core, which would free up more space. For example, the T47 does a small bend at Central right now: in a future revision, I would move Central in closer to the core so that the T47 could run in a straight line between BU Bridge and Union Sq, which would “tug” the northern branches of the Green Line and Red Line further in toward the center. (Looking at it now, I think this would also actually place Central in a more geographically correct location, for what it’s worth.)
Ironically, even though I’m talking about freeing up more space in the top left quadrant of the diagram, in all likelihood I would instead use that space to simply relocate the rest of the map upward, in order to free up more space in the bottom half. The centerpoint of the diagram is currently roughly at the Hatch Shell on the edge of the Charles. In a future revision, I would probably shift things so that the centerpoint is at Back Bay Station.
The busyness of Longwood and Dorchester
These are the parts of the diagram where the shape of the bus network is most germane. The criss-crossing lattice of the Dorchester network does not lend itself to simple labels like “to Ashmont” placed just south of Nubian (which would mirror what I did at Harvard and Sullivan). As for Longwood, the Bus Network Redesign will radically increase bus service to LMA, which definitely merits inclusion on the map, but is challenged by:
Fitting in labels for four bus routes on one segment (between Roxbury Crossing and Brigham Circle)
Fitting in a parallel-but-nearby route for the T47
Showing appropriate proximity to the E Line
Showing appropriate proximity to the D Line (farther away from the E Line)
Illustrating connectivity to Kenmore and Ruggles
Fitting in labels for the E Line and D Line
Fitting everything within the obtuse triangle defined by Copley, Kenmore, and Brookline Village/Riverway
I think the busyness can be partially alleviated by adjusting the compression of the inner core and re-centering the inner core a bit higher up in the diagram to open up a bit more space.
That being said, I think this is a conceptual shortcoming of the map: Longwood and Dorchester both represent areas where higher geographic fidelity is needed, in part simply because the topologies are complicated enough that the geographic representation already is pretty close to the maximally simplified representation of the network.
Unfortunately, this diagram is less effective at fitting in geographic accuracy the further away from the core you get. That’s why re-centering the diagram on Back Bay (or even something further south) is necessary – we need to provide more space for Longwood to fit comfortably within the inner zone.
Dorchester, on the other hand, will likely still have to remain within the “diagrammatic outer zone”, although I think it would also benefit from a little more “breathing” room. That being said, this may be where my design concept for this diagram really breaks down: I dislike the current diagram’s treatment of the Dorchester bus network because I think it looks confusing and hard to read, but I’m not sure mine does that much better.
The “starfish” design centered on Franklin Park feels pleasantly clever, but I worry is still too noisy. Likewise, I’m not wild about the physical disconnect: the bus line ends with an arrow, followed by a “To Destination” label, followed by a relatively small amount of blank space, followed by the diagrammatic stop label with the transfer label (e.g. the T16 going toward Forest Hills). Why not just extend the bus lines all the way to their destination?
(The reason I didn’t do that is because I’m using the absence of the bus and regional rail lines as a visual cue to the shift from geographic fidelity to diagrammatic lists. Now, it is true that the visual distortion would still remain so extreme that the transition would probably still remain visible. But, that corner of the diagram is already so busy that I’d be hesitant to layer on additional visuals.)
I suppose it could be possible to redesign the diagram such that the geographically accurate “inner zone” extends as far south as Forest Hills and Ashmont. Looking at the diagram now, that actually might be more feasible than it sounds, particularly with some compression and reduced scale, so I may need to play around with that!
Branches on the Green Line
The Green Line branches pose a problem: there are way more stops on the B, C, and D branches than there are on any other leg of the network (though Ashmont + Mattapan come close). What’s more, they are the only legs of the network that fan out to the side of the map, rather than the top or bottom, which makes the “diagrammatic list of stations” less obviously different in appearance. And on top of that, I ultimately wanted to make sure all three branches terminated “lower” on the map than Kenmore – meaning I couldn’t, say, turn the B Line upwards to fit it in as a list of stations.
I’m not thrilled with how the Green Line branches turned out, but I do think the concept can be sound, particularly if I can free up a bit more space to let me put the B Line labels on the outside rather than the inside (where they mix confusingly with C Line labels).
(One note: this design is meant to be future-proofed for an addition of a Needham branch: flip the D Line labels past Newton Highlands over to the left side, and use an upside-down tuning fork approach to add the Needham labels on the right, similar to the Red Line branches.)
Does the design concept of a geographic inner zone and a diagrammatic outer zone “work”?
Ultimately, I think the answer is “yes”: I think the fundamentals of this concept are sound, and it’s a question of execution.
As the “15-minute Bus Network” is rolled out over the next few years, it’ll be more and more important for the T to update its map to integrate those routes properly into the design. I hope that an approach similar to what I’ve illustrated here can be helpful in such a redesign.
Earlier this year, I described how Aldgate Junctions can be used to provide additional service along branchlines without impacting capacity on the core. But Aldgate Junctions have their limitations – a lesson that the Boston Elevated Railway (BERy) learned the hard way, 100 years ago.
The original Main Line El network
When what is now the Orange Line was first built, it was very different. In fact, the earliest iteration of the Orange Line did not use a single piece of track, tunnel, station, or right-of-way that the current Orange Line uses.
The Main Line El, as it was called, was opened in 1901, as a collection of three elevateds and one subway: the Charlestown El, the Washington St El, the Atlantic Ave El, and the Tremont St Subway. Yes – despite being opened less than 5 years before as a streetcar subway, the Tremont St Subway was semi-temporarily converted to third-rail and high-level platforms. (The four-track sections of the subway saw the inner tracks maintained for streetcars.)
The infrastructure of the Main Line El when it opened looked something like this:
Single els at the northern and southern ends were connected by a pair of downtown trunk lines, all linked together by a pair of Aldgate Junctions, the northern junction called “Tower C”, and the southern one called “Tower D”. This arrangement allowed all trains to run everywhere. For example, the following array of service patterns would have been readily achievable, with bidirectional service on each “line”:
(Note that I’m not sure a full service pattern like this ever existed; but, as you will see below, it looks like BERy experimented with many permutations, so this one may have been attempted at one point or another.)
Shifting into the Washington Street Tunnel and reshaping the network
The original network was short-lived. Within the decade, the Washington Street Tunnel opened:
As you can see, the Aldgate Junction at Tower C was preserved, but Tower D was modified into a simple flat junction. I argue that the asymmetric presence of the northern Aldgate Junction fatally undercut the Atlantic Ave El’s ability to contribute usefully to the network.
Mapping the lasting impact of the asymmetric Aldgate Junction
In the course of researching another project, I ended up doing a deep dive into BERy’s experiments with different service patterns on the Atlantic Ave El from 1919 to 1924. You can follow the evolution step-by-step below.
Ultimately, I would argue that the problem they were trying to tackle was a geometric one. Without an Aldgate Junction at Tower D, the Washington St El is hobbled by reverse-branching: every train you try to send from Dudley to Atlantic is one fewer train that you can send from Dudley to downtown; as it is today, downtown was the more popular destination and could hardly afford to lose service.
Trying out a shuttle service + deinterlining
This is why it is unsurprising that in 1919, BERy stopped running trains from Dudley to Atlantic via Beach St – all trains from Dudley would run through the Washington St Subway, as detailed in this newspaper announcement:
As you can see, BERy sought to increase frequencies on both the Tunnel and the El by isolating each other’s services; the Tunnel would be served by Forest Hills/Dudley-Sullivan trains, and the El would be served by North Station-South Station shuttles. (Not mentioned here is a dedicated track that existed at North Station, allowing Atlantic shuttles to reverse direction without blocking Tunnel traffic.) Drawing on the style of the Cambridge Seven Associates “spider map”, a diagram of the system at the time might have looked like this:
This was certainly a reasonable idea, and is a technique called “deinterlining” that remains in use to this day. (Every so often, you will see someone put forward a proposal to deinterline the NYC Subway, for example.) Two low-freq services offering dedicated one-seat-rides to multiple destinations are reshuffled into two high-freq services that provide higher frequencies to all stations, improve reliability, and maintain some OSRs, at the cost of turning other journeys into two-seaters.
The push for deinterlining highlights a common pitfall of Aldgate Junctions: it entangles all three branches into a single shared timetable. Trains on one branch need to be coordinated with trains on both other branches. Even if your train is bypassing a branch, delays on that branch will still impact your journey through ripple effects.
Pitfalls of a deinterlined main line + shuttle, and an attempt at remediation
But BERy’s own announcement reveals a fatal flaw in their plan: most of the major destinations on the Atlantic Ave El could be reached by other two-seat rides that were often more direct, especially for riders coming from the south. Why would anyone board a train at Dudley, ride it all the way to North Station, and then transfer to a shuttle and ride it the long way round to disembark at Atlantic (today’s Aquarium)? It would likely be significantly faster to transfer at State/Milk/Devonshire and ride an East Boston train one stop. (And probably would be just as fast to walk.)
And from a convenience perspective: a two-seater is a two-seater, so Washington + East Boston is equally convenient as Washington + Atlantic. At that point, journey time becomes the deciding factor.
Perhaps an Atlantic shuttle service could have been more successful if it had offered a southern transfer at Dover. Unfortunately, the Washington St El’s station construction style meant that significant capital investments would have been required to turn trains at Dover.
As it stood, the 1919 Atlantic shuttle service was useful for three specific things:
Shuttling passengers between South Station and North Station
Perhaps of limited use to long-distance travelers, but hardly a large market
Serving Battery St
Located at the farthest edge of the North End, with half of its walkshed underwater
Serving Rowes Wharf
Faced with declining ferry ridership and likewise only half of a walkshed
That is pretty wobbly, especially given the cost of maintaining the El and the diversion of rolling stock away from more heavily used segments.
Which would have looked like this (although I am unclear whether the Sullivan-Dudley service itself was weekends-only):
Implementing a “wraparound” service
The Dudley-South Station-Sullivan service – whether it was truly daily or only on weekends – only lasted another six months. In December of 1919, a fascinating “wraparound” service was instituted that essentially turned the Atlantic Ave El into a second northern branch of this predecessor to the Orange Line:
The core stretch through the Washington Street Tunnel would see 24 trains per hour (tph) at peak. To the north, 8 of those trains would head to South Station, while the other 16 would go to Sullivan; in essence, BERy “paid” for a one-seat-ride to the Atlantic Ave El by diverting about one-third of Sullivan trains.
(To the south, it should be noted, the 8 tph from South Station were short-turned at Dudley, again leaving the other 16 tph available to serve Forest Hills, though I’m not sure that they all did.)
Seasonal direct service
Sometime in the summer of 1920, a direct Dudley-South Station-Sullivan service was reinstated, to accommodate increased traffic from summer travelers. It’s unclear to me whether a North Station-South Station service remained during this time.
Once again, the wraparound service was discontinued. This time around, however, BERy reduced the frequency of the direct service lower than I believe they ever had before: only 5 trains per hour. This was again supplemented by a much higher frequency on the North Station-South Station shuttle, which saw 10 tph during rush hour.
I think there’s actually a lot to be said for this arrangement. The lack of wraparound services means that trains aren’t doubling back on themselves; the frequency for Dudley-Atlantic-Sullivan services seems to match the present-but-low demand, sitting at the edge (but still within) the realm of “turn up and go”; and frequencies remain high on the core segments, meaning that riders who are impatient have the alternative of a two-seat journey between services with high frequencies (and therefore short transfer times).
Reverse branching from the south
It’s unclear to me whether BERy returned to a “Winter” service pattern after the 1921 Summer was over, and if so, which Winter service pattern they used.
However, it appears that the Summer pattern was again used in Summer 1922, before being replaced in September 1922 with yet another new service pattern:
This pattern essentially extended the North Station-South Station shuttle – a relatively constant fixture of all these variations – from South Station to Dudley. This again turned the Atlantic Ave El into a second northern branch of the Main Line El, but shifted the split point to the south to avoid the roundabout journeys of the wraparound pattern. This of course came at the classic cost of reverse branching: radial service from Dudley was rerouted away from the core, reducing the number of trains that could run between Dudley and Downtown.
As I understand it, this service pattern remained somewhat stable, though I am unsure how long it remained in place. By 1924, the predecessors to the Blue and Green Lines saw many of their surface routes truncated at Maverick and Lechmere respectively, which leaves us a map like this:
Writing on the wall
In 1926, the Report on improved transportation facilities in the Boston Metropolitan District noted that (p. 26):
At the present time the Atlantic Avenue Elevated loop is utilized principally as a rapid transit connection between the North and South Stations. It also affords a convenient means of reaching the several steamboat and ferry terminals along the waterfront. The total traffic served by this loop is not particularly important in a comparative sense.
That same report called for the demolition of the Atlantic Ave El and replacing it with an “elevated roadway” (p. 41 and on) – essentially proposing the Central Artery, some 30 years before its time.
To be clear, there were a number of factors that put the Atlantic Ave El at a disadvantage. For one, running along the shoreline meant that half of its walkshed was literally underwater. The route also avoided the densest parts of downtown Boston, in favor of serving the docks, which also reduced transfer opportunities to the Tremont Street streetcar services and to mainline railroads at North Station.
(Transfer opportunities to the East Boston Tunnel were available at Atlantic, and to the Cambridge-Dorchester Subway at South Station; I would speculate, however, that passengers would likely prefer the shorter and fully-indoors transfers available on the Washington St Tunnel.)
Serving the docks was an understandable design decision at the time, but became more problematic as time went on. Tunnels under the harbor significantly reduced ferry ridership; for reference, the highly popular Boston, Revere Beach & Lynn Railroad ferried passengers across the harbor from their terminal at Jefferies Point to Rowes Wharf – surely a large source of passengers for the El.
Finally, it bears mentioning that Elevateds themselves quickly became unpopular. They were noisy, unsightly, and brought the noise of transportation up from street-level directly outside residents’ windows. Furthermore, since the Els were a rapid transit service that BERy used to express riders in from streetcar transfer hubs further out from downtown, stops were spaced distantly, and thus provided that much less advantage to residents who endured the costs of living nearby.
Would things have been different if Tower D had been maintained as an Aldgate Junction? It’s hard to say. Maintaining a central “loop” service as I showed in my diagram above would still mean reducing the number of trains that could run directly between Dudley and downtown.
On the other hand, a loop would have kept frequencies maximally high within the core Washington Street Tunnel, keeping capacity high for transfers from Cambridge, Dorchester, East Boston, and North Station. A loop service would also have created a one-seat ride from South Station to (what is now) Chinatown, State, and Haymarket.
Would it have been enough to save the Atlantic Ave El? In the end, I doubt it. The waterfront routing and probably the mere fact of being an elevated likely would have doomed it anyway. These were the early days of rapid transit – some ideas were simply best guesses, and so some ideas were inevitably wrong.
Lessons for today
It’s clear that the asymmetric availability of an Aldgate Junction following the construction of the Washington Street Tunnel is the fundamental reason BERy kept changing the service patterns seemingly every six months circa 1920. BERy was trying, I would argue, to solve a physically impossible puzzle, experimenting with basically every possible permutation of service on the El, and failing to make any of them work.
The history of the Main Line El offers a lesson, not in the benefits of Aldgate Junctions, but in the perils of reverse branching and doubleback services. A key advantage of an Aldgate Junction is the “branch bypass” service: recall BART’s Orange Line that runs from Richmond to the East Bay without entering the core in San Francisco.
In the case of the Atlantic Ave El, that advantage was negated: the experimental wraparound service was inefficient because it was a doubleback service that was roundabout and not fast enough to compete with more direct two-seat journeys. South Station-Sullivan service avoided the core of downtown, and consumed slots needed for the more valuable Sullivan-Dudley service.
Why does it work in London?
London’s example may be a closer comparison than the BART’s: the eastern end of the Circle Line is also a doubleback service, as can be seen in the 2015 London Connections Map:
Why does it work in London where something similar failed in Boston? I think there are a few reasons:
London has more people – a lot more people. Greater London had about 7.5 million residents in 1920, while Boston had a tenth of that (see pg. 143). Being physically smaller, 1920s Boston may actually have been roughly as dense as London, but you could probably fit (and I’m making a wild guess here) four or five “Bostons” into London’s areas of high density.
With that many people, the numbers game really begins to change. (This is a useful point to remember when comparing [Western] cities to London, New York, and to a certain extent Paris and Los Angeles – those cities are simply different due to their scale and are hard to use for comparisons.)
The northern and southern legs of the Circle Line are a little bit further apart than the El and the Tunnel were, increasing incentive for passengers to ride around the bend even if it is slightly more roundabout.
The Circle Line has fewer “crossing services” than Boston did: recall that riders could use the predecessors to the Red and Blue Lines to access most of the stops served by the El; London by contrast had more stops and fewer crossing services.
If you were coming from Farringdon or points west and wanted to go to Monument, you could alight from the Circle Line at Moorgate and transfer to the Northern Line and go south one stop… but if you were going to Cannon Street or Mansion House, then you’d need to get back on a Circle or District Line train anyway, so why not stay on? The Central Line and Thameslink also presented options, but might have been undesirable for other reasons (see below).
London’s large population becomes relevant when considering transfers; I don’t know what it was like in 1920, but today those segments of the Northern Line and Central Line are extremely crowded, while the Circle Line is noticeably less so. This again incentivizes riders to continue “round the bend”, to avoid an extremely crowded transfer.
Planning and crayoning
So what does all this mean from a transit planning and crayon mapmaking perspective? It means that an Aldgate Junction can solve some problems with branching, but it’s not a cure-all.
It’s still vulnerable to the pitfalls of reverse-branching, diverting radial services away from the core. Every train from Dudley that went to South Station was a train taken away from the more valuable Dudley-Downtown route.
If the branches are close together, then an Aldgate Junction becomes less useful because it won’t be used for through-journeys from branch to branch – there will be other “crossing services” (including walking or biking) that are faster. Someone journeying from Scollay Square to what is now Aquarium was better off traveling via the East Boston Tunnel than going the long way around.
If the branches are long and are corridors unto themselves, then the Aldgate Junction can still be a useful way to increase frequencies within the corridor – but in that case it may be more efficient and reliable simply to short-turn supplementary services within the branchline itself, rather than deal with the logistics of a junction.
In a Boston context, this would be relevant on the western branches of the Green Line: a “wraparound service” that jumps from the B to C Lines while avoiding Kenmore would be a poor alternative to the (idealized, well-running) 66, 65, or 47 buses. If frequencies need to increase within the Beacon or Commonwealth corridors, short-turning trains at Blandford St, St. Mary St or Kenmore would be more reliable and less complex than a junction.
(This also holds true, in my opinion, at the western end of those branches, where there is a true set of Aldgate Junctions at Cleveland Circle and Chestnut Hill Ave.)
An Aldgate Junction is more useful when as many of the following are true:
Branches are evenly distributed geographically
The region is pluricentric, where key destinations are located across multiple branches
The branches are long and form corridors unto themselves
Direct “crossing services” (such as circumferential routes) are not available between the branches, or are too centralized resulting in three-seat-journeys (such as Farringdon-Moorgate-Monument-Cannon Street)
Even before the elimination of the Aldgate Junction at Tower D, the Atlantic Avenue El failed all of these. Following the relocation into the Washington Street Tunnel, BERy was hamstrung with no way to serve the El without incurring reverse-branching, doubleback services, or both. This is vividly illustrated by the rapid changes and experimentation with service patterns circa 1920.
While the Atlantic Avenue El was demolished over sixty years ago, its history can still teach us lessons today.
Over the past week, I’ve been iterating on modified versions of the T’s official subway map to illustrate the closures and shuttle services that begin tonight and will continue for 30 days. This map will likely continue to evolve, and I will continue to post the latest revision here. As always, please note that this is not an official map — always refer to the MBTA’s website and to the City of Boston’s website for up-to-date information.
Notes for transit and design nerds
This exercise started relatively simple: show the Orange Line and northern Green Line in some alternate manner to indicate the bustituted segments. This was relatively straightforward: I borrowed design language from the Arborway bustitution in the late ’80s, with a colored outline, white fill, and colored circles for the stops.
On the further advice of someone with better aesthetic sense than I, I shifted the white fill to a lightly colored fill, to better differentiate the lines, and avoid the perception of a total absence of service. The light fill seemed to strike a good balance between maintaining the line’s identity, showing the continued existence of service, and also indicating a significant difference in service.
But, as happens with many projects, I kept on thinking of, “Oh, just one more thing I can add!”
Which brings us to the current design, which pushes the original map’s information design to the limits. I wanted to show:
The bustituted segments
The un-bustituted segments
Text notes on significantly relocated shuttle stops
The one-way service at Haymarket
The early-morning/late-night shuttle to Chinatown and Tufts Medical
The bus routes the T suggests as alternatives to the Orange Line (39, 43, 92, 93, CT2)
The suggested walking transfers between Orange Line and Green Line stations
That is a lot of information to cram onto a diagram that was originally designed to be rather sparse. The current official subway map is an evolution of a design from the early 2000s that primarily showed the rapid transit routes, with commuter rail and ferries being shown secondarily, and limited-access highways being shown tertiarily. In the late 2000s, the key bus routes were added, and a subsequent redesign shifted some parts of the map around while maintaining the same visual language overall.
Evaluating my attempts
Was I successful? Ehn.
I was pleasantly surprised when an earlier version of this map gained a small amount of traction of Twitter, so it’s nice to know that at least some people found it useful. But at a certain point, I fear the level of detail hinders rather than helps. Part of the brilliance of Cambridge Seven Associates’ original “spider map” design was in its simplicity; even if you didn’t memorize the whole thing, the visual concept was highly memorable: four lines, crossing each other in a square and radiating out. That basic schema was easy to recognize and recall, and created a foundation to understand the rest of the system, even if it wasn’t put into one single map.
The eventual addition of commuter rail lines, key bus routes, and now all of the additional information I’ve added here is all very reasonable, especially when done incrementally. But I find myself questioning the ultimate usefulness of the diagram I’ve created. Is it really useful enough for journey-planning? Or is it too confusing to parse?
Simple maps and specific signage
Ultimately, I’ve come to believe that clear and specific wayfinding signage in and around stations is much more important than a detailed system diagram, both under ordinary and extraordinary circumstances such as the Orange Line Closure. (This despite my own love for detailed system diagrams.) In that way, perhaps my earlier, simpler diagrams were more effective.
Shuttle routes only
In this simplest version, the shuttle routes are shown and nothing else:
The advantage of this design is how minimally it alters the original, and (hopefully) how starkly clear the changes are: the most important thing is that the Orange Line and northern Green Line are different and need to be planned around. The question all of this hinges on: can the diagram provide enough information to adequately re-plan the journey? And that’s the part I don’t know.
The second-simplest iteration added the walking transfers:
Including the walking transfers worked better than I expected. Quite frankly, I’d like to see these added to the official map (though hopefully a little more elegantly than I’ve done here). There are a lot of walking transfers that ought to be indicated on the system diagram, such as the ones I’ve included here, but also additionally:
State – Downtown Crossing
Government Center – Park
Riverway – Brookline Village
Reservoir – Cleveland Circle – Chestnut Hill Ave
Kenmore – Lansdowne
These transfers would not be suitable for everyone — and it should be noted that they are not free transfers under the current model — but if you are able-bodied and have a monthly pass that doesn’t charge per ride, these transfers are useful, speedy, and potentially can relieve congestion on key sections of the network.
Adding these transfers to the map is a good idea in general, but does it help in the case of the Orange Line & Green Line Closures? Again, I’m not quite sure. In most of these cases, I would guess that regular commuters are pretty familiar with the areas in question, and likely are well-aware that, for example, State and Gov’t Center are practically a stone’s throw apart. And if you aren’t a regular commuter… well, the pretty clear (and dire) direction from both the City and the T has been, “Please, stay away.”
Working on this diagram has been fun. It also has been nice to see positive response from numerous folks on Twitter. (Shout out to Jeremy Siegel at WGBH for sharing it with his followers!) And at least some of those positive responses have made comments to the effect of, “This is easier to understand than the materials the T has put out.” A few comments on Twitter aren’t necessarily a representative sample; however, the negative reaction to the T’s materials have been widespread and resounding — the Boston Globe going so far as to publish a parody of the official closure diagram.
That negative reaction suggests that there is room for improvement in how the T communicates these closures. I’d argue that the positive reaction to my diagram has been driven by its recognizable similarity to the “normal” map, combined with the clear-and-obvious differences that are blatant and draw attention to themselves.
With rumors swirling of partial shutdowns of the Green and Red Lines later this year, perhaps the T might consider adopting a similar strategy to what I’ve presented here.
Some of the earliest public feedback on the MBTA’s Bus Network Redesign (mapped in a previous post) came from residents of Somerville (and, to a lesser extent, Cambridge) who were – almost unanimously – unhappy with the proposals.
Based on my anecdotal observation on social media platforms, it appears that initial reaction from other communities has been more muted; this may change in the coming weeks with the further feedback sessions the T has planned. But still, I thought it was interesting that there was such an immediate and resounding response by comparison from Somerville.
I don’t envy the Redesigners their task with the Northwest Quadrant um, Sextant (?). Uniquely, they had to design for a system that doesn’t exist yet: GLX will be a seismic shift in transit access for Somerville, and while some of its effects are predictable, some are not. That’s a pretty big wildcard to toss into the mix.
The early signs suggest the Redesigners missed the mark, at least from the perspective of the community. I wanted to dig in to this and – of course – wanted to make a map to add to the conversation. I believe that I have been able to piece together a visualization that offers context and some explanation for this initial pushback; based on these, I have also generated some modest suggestions for revisions to the Redesign.
Further details are below, but the core of my suggestion is “swapping” the proposed T39 and proposed 90; this provides an increase in service to most riders, but is a more conservative change that does not disrupt existing travel patterns. This extension can be “paid for” by a dramatic shortening of the proposed 87 to its core service area, a reroute of the 90 to a shorter well-established corridor, and the use of a lower-freq crosstown route and a shuttle service to address connectivity gaps to Sullivan and Assembly.
I had two goals with this map: visualize frequency, and visualize potential destinations. I chose these goals because they reflected themes I saw in the initial feedback: frustration at multiple transfers (meaning, need for direct access to a larger number of destinations), and loss of service, particularly for lower-income residents (which I believe in some cases was a result of the Redesign’s shift away from “mid-low frequency” routes – think 45-min peak headways, that kind of thing).
Line color denotes reachable destinations. This system isn’t perfect, but I think captured some key dynamics.
Dark red lines reach Red Line stations
Dark orange lines reach Sullivan Square specifically, and light orange lines serve other Orange Line stations
Dark green lines reach Lechmere
Dark blue lines serve Longwood Medical Area
Some lines see multiple colors, meaning a rider might board a bus for multiple destinations; a good example of this is the 87 & 88 north of Davis, where a rider might board destined for Davis or for Lechmere.
Line width indicates frequency.
The thinnest lines have peak headways more than 30 minutes
such as the 85 or 90
The next size up, forming a large swath of the network, denotes headways between 15 and 30 minutes at peak, including
the 95 along Mystic Ave,
the 87 along Somerville Ave,
the 83 along Somerville Ave and Beacon St
Thick lines indicate peak headways of 15 minutes or better – matching the target for the Redesign’s frequent network, and including major corridors along
The thickest lines – matching the width of the rapid transit lines – see peak headways of less than 10 minutes, including
the cumulative 87 & 88 between Davis and Clarendon Hill,
the 101 & 89 on Broadway running into Sullivan
Here’s a version of the current system only showing routes that see 15-min peak headways or better.
Here we see six distinct corridors emerge:
Medford Square (and Malden) – Main St – Broadway – Sullivan
Powder House Square – Broadway – Sullivan
College Ave – Powder House Square – Davis
Clarendon Hill – Davis – Highland Ave – Lechmere
Arlington Center – Porter – Harvard
Sullivan – Union – Harvard – Allston/Brighton and Reservoir
I then created a map using the same design language to visualize the Redesign proposal.
(I recommend opening the “before” and “after” images in separate tabs, and then switching between them to hone in on the differences. I tried creating a GIF, but was unsatisfied with the results.)
Impact to current high-freq corridors
Let’s first review the impact to the current high-freq corridors:
Medford Square (and Malden) – Main St – Broadway – Sullivan
Goes near but does not provide transfer to GLX at Ball Sq
Extended beyond Sullivan to provide a (long) one-seat ride to Lechmere and Kendall
Powder House Square – Broadway – Sullivan
Moreover, this route is actually composed of a pair of branching routes:
a mid-freq route to Davis
a low-freq route direct to Clarendon Hill
Davis and Clarendon Hill lose direct service to Ball Sq GLX and Broadway
Davis and Clarendon Hill maintain roundabout access to Sullivan via Mystic Ave, an increase of 0.5 miles
College Ave – Powder House Square – Davis
Intact and strengthened
Newly anchored at north by Medford/Tufts GLX and extension to Medford Sq
Worth noting that the twice-hourly one-seat ride beyond Davis to Porter and Harvard is eliminated
Clarendon Hill – Davis – Highland Ave – Lechmere
Significantly reduced, and partially eliminated
Clarendon Hill – Davis gets a pair of the Redesign’s “30-min-or-better” routes, which could approximate 15-min headways, but still does not meet the current service’s average sub-10-min frequencies
Highland Ave drops into the Redesign’s “30-min-or-better” routes, but does not connect to Lechmere, or to Union GLX, or even to Gilman GLX (though it comes close), but instead is rerouted over toward Sullivan… which it doesn’t actually reach, instead ultimately diverting to Assembly
Arlington Center – Porter – Harvard
Sullivan – Union – Harvard – Allston/Brighton and Reservoir
Sullivan – Harvard is maintained, and combined with through-service to Everett
However, ridership from one side of Harvard to the other is actually surprisingly high, so this elimination is not trivial
Of the six current high-frequency corridors, three are maintained and three are significantly impacted. This does seem counterintuitive – as far as I can tell, all other existing high-freq corridors across the system were maintained in the Redesign, and most were significantly strengthened. I suspect the difference in Somerville was the future presence of the Green Line Extension.
Green Line integration (or lack thereof)
One of my biggest surprises on seeing the Redesign was how little integration there was to the GLX stations. Ball Sq and Gilman Sq will both see bus routes pass less than a quarter mile from the station without offering door-to-door service.
In addition, despite the arrival of the Green Line, Union Square now sees less connectivity than it did before, including the loss of one-seat rides from Clarendon Hill, Davis, and Kendall. As Councilor Pineda Neufeld pointed out, this also reduces access to the Market Basket in Union Square, as well as the Star Markets on Beacon St and Elm St.
I would argue that the Redesign treats the Green Line Extension more like one of its high-freq bus routes than like a rapid transit line – as if the GLX has said, “Don’t worry buses, I’ve got this stretch”, and thus bus routes are routed away from it. That is not done with any other rapid transit lines, and with good reason: rapid transit access is concentrated in discrete areas around stations; a key role of surface transit is to provide access to a station from beyond its walkshed. Unlike rapid transit, the close stop spacing of bus routes provides continuous access along the entire route, which GLX lacks.
To be clear, for over a century now, Somerville’s surface transit routes have had to play double-duty, providing both feeder service into rapid transit stations, as well as longer-distance service to support journeys that would in other areas be covered by rapid transit. GLX relieves them of the second burden, but not the first.
To wit: the entire Red Line from Davis to Kendall is doubled by surface transit routes in the Redesign. It is true that GLX’s stop spacing is closer than the Red Line’s, but it’s still well-above typical surface transit stop spacing. The Green Line is not a wholesale replacement of local buses.
Highland Ave vs Elm St & Somerville Ave
In the current system, Highland Ave sees mostly 15-min-or-better service at peak on the 88, from Davis to Lechmere. Pre-pandemic, the average AM Peak frequency was 10 minutes. (The 90 layers on about one trip per hour to Sullivan.)
(A short stretch of half-a-mile between Elm and Park Sts on the northern half of Somerville Ave sees additional 20 minute headways on the 83, running to Central Square via Inman. North of Elm, the 87 and 83 split, though remain only a couple of blocks apart for some distance. Pre-pandemic, the 83’s average AM Peak frequency was also 22 minutes.)
In the Redesign, Highland Ave drops into the 30-min-or-better category, and loses direct connections both to the Green Line and to Sullivan. (I should again note that 30-min-or-better routes still may see high-frequency peak service, which perhaps is the vision in this case.)
By contrast, Somerville Ave sees a significant increase: the 83 holds its place, while the 87 between Union and Porter is supercharged as the T39, receiving 15-min-or-better service. Somerville Ave also maintains a direct connection to the Green Line – only one of two radial routes in Somerville that do so, the other being the T96.
In essence, the Redesign swaps the frequency tiers of Highland Ave and Elm St & Somerville Ave. As mentioned above, Highland Ave is one of the current high-freq corridors, so its exclusion is puzzling.
I am guessing that the Redesigners saw the extent to which the 88 parallels GLX, and believed the Green Line would be an adequate replacement. As discussed above, however, surface transit and rapid transit are different beasts; the 88 is being relieved of its rapid transit duties by GLX, but not its surface transit duties.
Moreover, while it’s true that the 88 parallels GLX for a lengthy distance, they diverge significantly after Magoun Sq GLX – GLX aims for Tufts and beyond, while the 88 aims for Davis and beyond. And as numerous people noted in the reactions I linked earlier, the 88’s corridor north of Davis is not meaningfully accessible from GLX.
Increasing frequency on Somerville Ave is not necessarily a bad thing – the problem is how the increase is achieved. The current Somerville Ave corridor runs uninterrupted from Clarendon Hill to Davis to Porter to Union to Lechmere. The Redesign shears off the southern half of this corridor, and joins it to an extended T39, running Porter to Union to Central and beyond to Longwood. That is a bold proposal, but it also dismantles a one-seat ride that has been in place for over a century.
This reflects a larger challenge introduced by treating the Clarendon Hill buses as feeders to Davis Sq, rather than acknowledging their actual roles as parallel spines threading the city together, radiating not from the Red Line at Davis, but from the Green Line at Lechmere.
Lack of through-running from Clarendon Hill
It is worth highlighting that the current system offers one-seat rides at least half-hourly from Clarendon Hill to:
Powder House Square
The Redesign reduces that list significantly:
Powder House Square
Sullivan station (bus journey lengthened by half mile)
Southernmost Broadway, near Sullivan
Ball Square (via a 6 minute walk)
Most of Broadway
For over 100 years, Somerville has been tied together by crosstown routes on Highland and Somerville. The Redesign makes the unfortunate decision to reduce the Highland corridor, and breaks what is currently a single seat journey across the city from Clarendon Hill to Union Square via Somerville Ave into an almost-certainly three-seat journey.
On paper, it may look like Clarendon Hill is all set with feeding into a hub at Davis; in reality, the Redesign takes numerous journeys that have been single-seat rides for – again I emphasize – over 100 years and makes them essentially impossible.
I want to emphasize that I don’t mean to besmirch the Redesigners or their efforts: this was a herculean task that is impossible to get perfect. Tradeoffs had to be made, and balances struck. I can understand how they arrived at their current proposal, and I also can understand why community members are deeply unhappy.
In this post, I have attempted to detail the nuances of the current system, to illustrate some of the features that I believe underlie many of the criticisms that have been levied against the Redesign. I want to conclude by offering some modest suggestions for revising the Redesign to address the concerns that have been raised.
Methodology and fudge functors
While I am not sure that it has been stated explicitly, I believe the Redesign was undertaken with a “net zero” assumption – meaning the Redesigners assumed they could only work with the existing buses the system has today, and not increase the number of buses overall. As such, I am going to frame my suggested modifications through a reallocation lens: if I propose lengthening one route, I will attempt to balance it out by shortening another.
There are also fudge factors at play here that may provide some wiggle room on these proposals. First, infrastructure upgrades such as bus lanes and transit priority signaling may enable faster service and thereby reduce the number of buses needed to maintain frequencies. Second, it may be possible to spread minor frequency decreases across multiple routes to free up enough buses to add a new route – enabling the creation of a new high-freq route without eliminating routes elsewhere.
These fudge factors cut both ways, of course – in some cases, they may make things harder, not easier. So while I’ve done my best to consider these suggestions as carefully as I can, I am of course limited to the data available to me; these suggestions should thus be considered preliminary.
Shorten the proposed 87 along Mystic Ave to terminate at Harvard St
Shorten and reroute the proposed 90 to Union Sq GLX via Somerville Ave (essentially recreating the current 87’s route)
Institute an MBTA-run frequent shuttle service between Sullivan and the Assembly Row development, potentially leveraging public-private partnerships
Cumulatively, these modifications generate a surplus of 6.18 “route-miles” at 30-min-or-better frequencies.
Utilizing the surplus
Reroute and extend the proposed T39, running Union Sq – Highland Ave – Davis – Clarendon Hill
Revise the proposed network to include a 60-min-or-better route running Davis – Highland Ave – Sullivan, along the corridor of the current 90 (it may be possible to run this service at 30-min-or-better)
Suggested revisions in review
The core of my suggestion is “swapping” the proposed T39 and proposed 90; this provides an increase in service to most riders, but is a more conservative change that does not disrupt existing travel patterns. This extension can be “paid for” by a dramatic shortening of the proposed 87 to its core service area, a reroute of the 90 to a shorter well-established corridor, and the use of a lower-freq crosstown route and a shuttle service to address connectivity gaps to Sullivan and Assembly.
As detailed in my appendix, I believe these changes
are achievable with a net-zero impact on the overall Redesign
maintain better continuity with established travel patterns and community corridors
still provide specific and general enhancements of service to most riders, per the Redesign’s objectives and philosophy
I commend the Redesign team on their thorough and innovative work. I hope they will carefully review these suggestions and the further feedback provided by the community, and consider adopting these changes into a revised version of the Bus Network Redesign.
Thank you, as always, for taking the time to read!
In short, the MBTA is undertaking its first bottom-up redesign of its surface transport network in 100 years. The vast majority of the T’s bus routes once were streetcar routes; some routes have seen minor-to-moderate modifications in the ensuing decades, but the need to avoid disrupting the live system — which governs the day-to-day realities of thousands of people — has always capped how much could be done. As part of the long-running Better Bus Project, the T has conducted a deep dive review of its existing routes, including their ridership and reliability (see the Better Bus Profiles) and user research speaking directly to riders and community members.
Years in the making, the T this month released a proposed redesign of its bus network — details at the first link. This is a massive undertaking, and I give the redesigners credit for very clearly trying to avoid the “We’ve Always Done It Like This” Syndrome that plagues so much of American transit planning (especially in Boston).
Like any proposal, it has its imperfections and flaws. From my perspective, there are some things I like, and some things I don’t. There already has been some initial community feedback, and the T has a docket of public meetings (in-person and virtual) through mid-summer to collect feedback.
For the most part, I don’t intend to use my platform here to evaluate the merit of these proposals. The most important voices here are those of community members — their opinions should be listened to first, and given paramount consideration. Instead, my hope is to add to the discourse by providing additional ways to view and conceptualize the redesigned network — mainly through maps.
(There is one area of the proposal which received swift and strong public criticism. I have a post, and a pair of maps, in the works on that, where I will attempt to illustrate the flaws that have been pointed out by the community, and hopefully offer some modest suggestions to improve the proposal to address those problems. Stay tuned.)
In this post, I will share a map I have created to illustrate the Redesign’s “15-minute network”: a series of bus routes that are proposed to have 15-min-or-better headways all day from 5am to 1am, seven days a week. I’ll use the map to highlight some system-level features of the Redesign, and hopefully provide a framework for deeper discussion.
Very few circumferential or crosstown corridors — almost everything was radial
Morning peak frequencies were often higher than afternoon
The bus network “breathes”
An entire subnetwork of high frequency services turns on and off during the peak, providing much more comprehensive service during rush hour, but a signficantly sparser network during middays, evenings, and weekends
The entire northern quadrant of the network — everything between the Red Line and the Blue Line — was bereft of (intentional) high-frequency all-day routes, with the sole exceptions of the 111 in Chelsea and the 116/117 in Chelsea/Revere
Some communities, like Everett, don’t show up on the “Gold Network” (high freq all day) because they are instead served by a more diffuse number of routes spread across the city, operating at lower frequencies
The absence of the North Shore network — meaning the absence of consistent high frequency service — was conspicuous
The Dorchester network is one-of-a-kind, with features that don’t exist elsewhere
The network itself is actually three networks superimposed: a “10-minute all-day network”, a “15-min peak, low off-peak network”, and a “low frequency network” — most routes fall very cleanly into one of these three buckets
(Interestingly, that last point about the Dorchester network[s] seemed to be on the mind of the Redesigners as well — they’ve also adopted three primary tiers: a “≤15-minute all-day network,” a mid-frequency network that I’m guessing will be “15-min peak, 30-min off-peak”, and a low frequency network that, like Dorchester’s, would mostly see hourly services. I won’t really go into much detail here, but in my previous analysis, I did note consistent characteristics about each of the Dorchester subnetworks, and I see many of those ideas applied systemwide in the Redesign.)
I mention all of these points because I believe the Redesign recognized these features as well, and explicitly designed their proposal to address them.
The Proposed 15-Minute Network
The Redesign calls for a series of 26 high-frequency routes that would see 15-min-or-better headways all day everyday from 5am to 1am. This proposal goes much farther than the system I described above — in particular with its commitment to late night and weekend service. Vanishingly few corridors see any level of service approaching this currently. Routes on this network would be indicated by a “T” prepended to their route number: the T39, the T111, and so on.
I’ve spent a while digging through the weeds of the Redesign, and have concluded that the 15-Minute Network is composed of three kinds of routes.
These are straightforward: routes that radiate out from the core, and which feed into major transfer stations such as Harvard or Forest Hills. On my map below, I have used a dark blue for these routes. Most of these routes are unsurprising, and many of them are identified on my Gold Network map above.
These routes offer crosstown service that goes around the core rather than pointing toward it. Some of these routes behave like radial routes as they approach their terminals; for example, the southern half of the T96 essentially radiates out from Porter and Davis. So these routes still will be used by commuters going to downtown — but they also will enable journeys between multiple subway lines that can avoid going all the way to downtown. The T1 is a classic example, connecting Roxbury and Cambridge without requiring riders to change at Downtown Crossing.
There are two proposed routes that do not fit cleanly into the categories above or below: the T109 and T101, both running through Sullivan. North of Sullivan, they behave clearly like radial routes, to Medford/Malden, and to Everett/Malden. South of Sullivan, they do something that bus routes historically have not done: continue on from one transfer station to another.
Traditionally, these would be considered circumferential routes. However, I have mapped them as radial routes — I believe the Redesigners are trying to reconceptualize these corridors as radiating instead from Harvard and from Kendall, passing through Sullivan somewhat incidentally. I of course have no insight into their actual thought process, but I think it reflects general trends they’ve shown in favor of longer routes that pass through multiple quadrants of the system.
Longwood Medical Area Routes
This is by far the most seismic shift in the redesigned network. For the first time, Boston is proposing a transit network that acknowledges that Longwood is a major employment center, a third “downtown” equivalent to Back Bay and the Financial District. See for yourself:
The Redesign proposes extending most major routes from Ruggles beyond to Longwood; it extends Cambridge crosstown service beyond Central to Inman, Union, and Porter; it adds a new crosstown route to the Seaport; and it increases frequencies on most existing routes.
When I did my analysis in 2020, the Kenmore-Longwood-Ruggles corridor saw 15 buses per hour during the morning peak, 4 per hour midday, and 6 per hour during the evening peak. The Redesign notes that exact routings through LMA are tentative pending further study, but by my count, the number of buses per hour between Longwood and Ruggles, Nubian, or Roxbury Crossing is proposed to increase to at least 20 buses per hour, all day.
I’ve colored the Longwood routes in dark red on the map. Some also act as radial routes to other hubs, and some do double duty as circumferential services in the larger network. But Longwood is undeniably the center of gravity, and makes for a distinct subnetwork, worthy of its own identification.
A few additional notes here:
This map is my creation, based on materials published by the MBTA; it is not an official map and any errors are mine. I recommend using my map as a jumping off point before reviewing the official materials.
Each route is marked separately and indicates a minimum of 15-minute headways (4 buses per hour) all day every day — I am sure that many if not most routes will see significantly higher headways during peak
Certain major bus stops are indicated, largely for the purpose of indicating transfer points to rapid transit; stop placement is not exact
Some potential “transfers” would require some walking, indicated by a dotted black line
The proposed Blue-Red Connector and potential Silver Line Extensions are indicated with dotted lines
Some corridors see high-frequency service provided by layered mid-frequency services; these are mostly indicated by the line splitting and ending with arrows
This map is not precise and is meant to illustrate the overall network, not detail individual routes
Some routes have been simplified to reduce clutter. For example, the T39, T9, T70, and most of the routes in Chelsea, all have significant stretches where the route splits on to parallel one-way streets; most of these, I have simplified by drawing the route through the block in between the streets
Here’s a detail view on Back Bay and Longwood, probably the most visually cluttered part of the map:
I do want to emphasize again that I am not trying to evaluate the quality or suitability of the Better Bus Project’s Bus Network Redesign proposals. There are elements of the proposal that I believe are transformative in that they are shifting the conversation in ways that are vitally necessary: centering Longwood, insisting on consistent high frequencies all day everyday, and creating wholesale new corridors that do not descend from the old streetcar network.
But the devil is always in the details, and there are many details to sort through in this proposal. My hope is that my overview and map can make it easier for you to wrap your head around this sprawling project, and from there, dive into the details, well-armed with a larger context.
Some time ago (before the pandemic), I considered taking a job in New York City. Having no desire to relocate, and understanding that there would be some flexibility for how often I actually needed to be in the office, I pondered whether I would be interested in becoming a “super commuter”.
What is a “super commuter”?
According to most definitions I’ve found, a super commuter is someone who lives in one city/metropolitan area but works in another. This seems like a somewhat uselessly vague definition, at least in the Northeast Corridor, but (with apologies to Justice Potter Stewart) you definitely know a super commute when you see it.
Most super commuters do not go to the office five days a week, which is one reason they are willing to make the longer journey. For my part, I’d argue that a super commute is one which takes, let’s say, 2.5 hours or more one-way.
This definition probably encompasses more commuters than Moss & Qing’s analysis did, but it seems to me that travel time is more likely to affect behavior than raw distance or crossing MSA boundaries. Philadelphia-NYC takes 1h50m by Amtrak, but numerous Metro North journeys are comparable, such as from Poughkeepsie (1h50m), Wassaic (2h), Danbury (2h), New Haven (2h), or Waterbury (2h45m).
Amtrak schedules for super commuters
In any case, as I began to ponder this lifestyle change, I started looking at the Amtrak schedule. From what the hiring officer had told me, it would be alright for me to do some flexible hours when I showed up at the Manhattan office — for example, it’d be fine to arrive around 10:30, and then either leave at 3 on a short day, or put in the extra hours and leave around 6 or so.
Morning inbound journeys
Christopher Juckins’ Amtrak schedule archive lets us review Amtrak timetables from before the pandemic (and before Amtrak stopped publishing PDFs on their website). As can be seen on the Boston-Washington Northeast Corridor schedule, getting into Midtown from Eastern New England for a 9am start is barely doable, but additional options open up as the morning goes on:
In summary, journeys which arrive in NYC before lunch included:
5:05am to 8:47am
6:05am to 9:47am
6:10am to 10:22am
7:15am to 10:47am
I figured I would probably aim for those 6am departures, maybe with some of the 7:15’s mixed in. That seemed manageable to me.
Afternoon & evening outbound journeys
So then I took a look at the trip home. There are too many trips to took a screenshot, but in summary:
3pm to 6:46pm
3:30pm to 8:12pm
4pm to 7:40pm
5pm to 8:50pm
5:38pm to 10:10pm
6pm to 9:45pm
7pm to 10:50pm
7:50pm to 12:20am
Now, to be fair, some of those later trains really do get you home quite late. But that 4pm trip in particular struck me as perfectly fine — especially if your job is one where having uninterrupted time at the beginning and end of the day is valuable (for example, time to write or read). That could really work (and held some real appeal to an introvert like myself).
But the other thing that struck me was, “Damn. that’s a better schedule than the MBTA Commuter Rail.” Hourly departures, predictable journey times, a couple of extra trips layered in? Not bad!
And this got me thinking… there are several other corridors that feed into NYC; do they all have frequencies to support this super commute?
And by now, you surely can guess that that is true (otherwise there would be no post!). I have some further observations in the appendix below about individual routes (which I think are worthwhile reading, as they illustrate what a behemoth the Northeast Corridor is), but the main reason I’ve written all this is as prelude to a map:
This map treats Amtrak’s services into New York like commuter rail services — and I would argue that they essentially are indeed a “super commuter rail” network. All of the stations and routes marked on this map have the ability to support the kind of “super commute” I was considering for myself: leave home early, get to New York mid-morning, leave New York mid-afternoon-ish, get home late, repeat once or twice a week, depending on distance.
Scope of the network
As you can see, it’s actually quite a sprawling network — stretching from Albany to Washington, Boston to Harrisburg, close to 200 miles in each direction. Boston, with the itineraries I listed above, is actually on the extreme end of the network, with its ~4h travel times; a place like Wilmington, DE is a mere 1h40m journey, comfortably below Metro North’s longest journeys (and in significantly more comfortable seating). Hartford, CT and Lancaster, PA are both about a 3h journey.
All of the journeys depicted on this map are available via services with modest frequencies (to enable flexibility) and a short enough travel time to accommodate a same-day round trip.
Local and express tiers
One of the things that was fun about making this map was poring over the different timetables to look at which stations were frequently served. For example, the Northeast Corridor schedule for NYC-Washington lists out a whole bunch of stations, which most trains then skip. Despite the timetable listing 8 stations between New York and Philadelphia, most trains only stop at 4: Newark Penn, Newark Airport, Metropark, and Trenton.
In this way, Amtrak builds an informal tiered network akin to a local-express model. Virtually all trains stop at places like Stamford, Trenton, and Rhinecliff; some trains skip stations like Kingston, Poughkeepsie, or Downington; and then there are some stations, like Princeton Junction and Newark, DE, which may only get one train a day, or even less (spiritual successors to “whistle stops”). Acela service mainly restricts itself to the major stations, leaving the Regionals to pick up the leftovers.
The big picture
Amtrak (and/or the City of New York) would do well to publish a formal map like this, one which highlights that these are routes with high frequency service, modest journey times, and flexible schedules, and one which likewise differentiates between different service levels at each station. This network is a tremendous success story for Amtrak, and for American rail in general.
A map like this also illustrates what is possible with a strong piece of core infrastructure — in this case, the Northeast Corridor. Even communities which aren’t directly on the Northeast Corridor, such as Harrisburg, Springfield, or Albany, are able to benefit, as it becomes possible for them to “tag along” for the ride.
When advocates talk about high speed rail in places like Texas, Florida, or the Piedmont Corridor, it’s not just about connecting Atlanta to Charlotte, but about building a core piece of infrastructure that then enables branch lines to be built to Birmingham, Chattanooga, and Augusta. High speed rail infrastructure not only enables long-distance travel (for business or pleasure), it also enables daily commutes — and super commutes.
There are many ways to draw crayon maps – many more than could fit in one post. In this post I will talk about the software that I use to create maps for this blog.
Really we should be starting with something more fundamental like “pen-and-paper” or “the ideas”. But, assuming you’ve got some of the basics in mind, one of the big questions next is the software. (Although, don’t underestimate the effectiveness of a good hand-drawn diagram that is scanned/photographed and uploaded! No need for software if you feel like going old-school.)
It’s worth distinguishing two kinds of goals one can have with transit maps and diagrams. First, one can focus on elegant design solutions (especially for existing systems); TransitMap.net is a great blog that focuses on transit map/diagram design. Second, one can focus on conveying detail, particularly of proposed systems, with less focus on “looking good”. While these two obviously overlap in significant measure (elegant design also usually is particularly good at conveying detail), my focus is usually on the latter more than the former.
Put another way: I don’t worry too much about my diagrams looking pretty. In my case, this is somewhat self-serving, because I don’t have the know-how to make good-looking diagrams at a pro or even semi-pro level. But put more positively: this also means that you don’t need to worry about getting your diagrams to look good either! Don’t let that be a barrier to getting started!
Okay, but actually, what software should I use?
Okay, sorry for getting distracted. The short answer: start with what you have, and then try some of the ones I suggest here.
Microsoft Paint or Paintbrush (for Mac)
I can guarantee you that any designer who happens to read this post will physically grimace at this suggestion, so I do want to be clear that both of these programs are extremely limited; if you are going to use them, keep things simple: straight lines, 45-degree angles, simple text.
That being said, especially when you just want to sketch something out, Paint is a very useful tool, precisely because of its simplicity. With some effort and care, you can indeed use it to make clear, straightforward diagrams.
For example, this is something I threw together in MS Paint just now, illustrating a possible commuter rail network for Rhode Island, with the existing MBTA Commuter Rail line, a new RI Commuter Rail service from Worcester to Westerly, and an extra layer of local trains running between Pawtucket and TF Green:
Is it pretty? No, not really. Is it even particularly clean or neat? No – my spacing of station names is inconsistent, the size of the station markers varies, and the bends of the lines are a bit sloppy.
But does it convey the information I needed to? Yes. Station are clearly and legibly marked (yes, I got tired of labeling the MBTA stations), the service patterns are clearly indicated (at least I hope they are clear – can you tell which stops the MBTA skips?), and there are enough nods to geographic fidelity (such as the curve through Providence) to provide context for the viewer.
And while it’s true that a lot of the details are sloppy, the overall design is generally symmetrical and balanced, the stop spacing is mostly even, and the visual is streamlined and simplified – all of which means that even though the design itself is hardly inspired, it’s also not going to be too distractingly bad.
(To editorialize briefly: there is something to be said for transit diagrams and transit proposals which are straightforward enough to visualize using Paint.)
There are several downsides to using Paint, though. As mentioned above, you can get clear diagrams – “with some effort and care”. The time and effort is where you pay the price. It takes a while to do simple things nicely with Paint, and it takes a long time to do complicated things at all.
If you’re just getting started, I highly recommend playing around with Paint a little bit – get a feel for what “looks good” in the kinds of diagrams you’re making, but aim to “level up” once you can.
Metro Map Maker
This website lets you make transit diagrams from scratch, or remix those created by other users. It is very simple to learn, and can be pretty fun to use. That said, I myself don’t use Metro Map Maker, and I think there are a couple of things to bear in mind if you choose to do so.
First, I myself find the interface “fiddly” and difficult to draw things precisely the way I intend (which is my main reason for using a computer rather than sketching something by hand). I think this is visible in some of the maps in the gallery, some of which are quite clean and clear, and others of which struggle a bit. In particular, I have a hard time with the way Metro Map Maker renders Y junctions, where two branches feed into a single trunk; the way Metro Map Maker does it, it’s very easy to mistake those for three-way junctions.
The other thing to be aware of is that Metro Map Maker diagrams sometimes get poo-pooed by folks on aesthetic or “professionalism” grounds. There are some venues where such criticisms are appropriate – I would not, for example, recommend that transit advocates use this site to create visualizations of the services they are advocating for. But, especially if you’re just doing this for fun, I think it’s a perfectly reasonable tool. Just keep in mind who your audience is!
This is my application of choice these days, and the way I create most of the visualizations on this blog. (Unfortunately it is Windows-only, and I haven’t yet found a Mac equivalent that has the same “sweet spot” of features.) Paint.NET is available on its website and on the Windows store.
For me, Paint.NET has an excellent balance of ease-of-use and useful-features. Eventually I plan to “graduate” into one of the programs listed below, but for now, I’ve gotten pretty darn good with Paint.NET, so I’m sticking with it for now.
One of the biggest reasons to use Paint.NET instead of MS Paint is the ability to use layers. For example, let’s say that I’m drawing up plans for Super High Speed Rail between Boston and New York, but I’m trying to decide between an alignment via Hartford and an alignment via New London. In MS Paint, I’d have to settle for a workaround: draw both using different colors, make a copy of my file after drawing the Boston-Providence and NYC-NH segments and work on two separate diagrams, or just pick one and forget about the other. In Paint.NET, on the other hand, I can just create a new layer for each alternative, and show/hide them depending on which version I want to look at.
You can also use layers to add and hide different levels of detail. For example, in one of my big maps, I have the local bus routes drawn in a layer of their own; I keep it hidden most of the time to reduce clutter, but sometimes show it in order to see things in full context.
I also recommend isolating lines, station markers, and labels each into their own layer. This will make it easier later on to make quick changes en masse, such as changing the color of a line.
Paint.NET still has downsides. It produces raster graphics and not vector graphics, which means things are pixellated when zoomed, and you actually physically cannot create pure curves (although if you are zoomed out reasonably, no one will notice the difference aside from professional designers). And as far as I know, Paint.NET has no concept of “linked objects”, meaning that if you create a fancy icon as a station marker, you’ll have to copy and paste it each time you want to use it, and you’ll have to manually modify every single copy if you want to make changes later. (This is why I just use a simple black circle for my station markers.)
Overall, however, I’ve found Paint.NET to be extremely useful.
Inkscape and Adobe Illustrator
Now we have “graduated” into the top tier: vector graphics. These are the programs used by professionals, and damn can you make things look good with them! Vector graphics allow you to infinitely zoom without pixelation and draw perfect curves without jagged edges.
Adobe Illustrator is part of the Adobe Creative Cloud suite (along with the perhaps more famous Adobe Photoshop program). Inkscape is open-source, and available for free.
Becoming more comfortable with Inkscape is a medium-term goal of mine, but it’s not a tool that I am experienced with at this point. So, for once, I don’t have much to say on the topic. But if you get the opportunity to practice with either of these programs, I highly recommend it!
What about Google Maps?
Good question. You also may have questions about using Paint.NET specifically, or what I’m talking about in the footer of my blog about “basemaps” (and why I have that footer in the first place), or why I’ve been talking more about “diagrams” than about “maps”. All great questions! I hope to get to them in a subsequent post. In the meantime, hopefully I’ve given curious readers enough to get a running start! Have fun crayoning!
One peculiarity of this whole situation is that most of the options for “Phase 2” are available from both the Riverbank alignment and the Kendall alignment. They aren’t fully interchangeable, but there is a surprising amount of overlap, and most of them can be discussed largely independently of which Phase 1 alignment is used to reach them.
The modern incarnation would see the Blue Line taking the most direct route from its Phase 1 terminus and then running out west parallel to the Worcester Line tracks.
Unfortunately, the 1945 proposal was made before the construction of the Mass Pike east of 128. For those who don’t know, this part of the Mass Pike was constructed by taking land previously occupied by railroad tracks; this stretch once had four or more tracks, like the Southwest Corridor did at the time. The vision would’ve been quite similar to today’s Southwest Corridor: take a couple of tracks and devote them to rapid transit, and leave the rest for mainline rail.
Now with only two tracks, it’ll be much harder to enact that vision. If you wanted to be bold, you could propose reclaiming land from the Mass Pike, but good luck with that; likewise to building a cut-and-cover subway, or an elevated.
In today’s climate, this stretch is much more favorable to an Indigo Line-style service, with perhaps 4 local trains per hour making all stops to Riverside supplemented by 2 trains an hour that run on to Framingham (with 2 additional trains expressing through on the journey to Worcester). This would provide modest frequencies while maintaining a single mode of service. (And, for what it’s worth, would still leave the door open to building a subway or reclaiming some of the Pike later — the capital improvements to support Indigo service would still benefit continued mainline use, even after the construction of HRT extension.)
Blue to Riverside (and Needham)
This is probably the most important one to discuss. Extending the Blue Line to Riverside (usually via Kenmore, though occasionally via Huntington) is frequently proposed by amateur transit planners, and is reflective of the D Line’s unusual nature as a Green Line branch: being a converted railroad line, it has rapid transit stop spacing, akin to the Blue or Orange Lines, unlike the other Green Line branches, which stop every few blocks. If you were going to replace one branch of the Green Line with the Blue Line, there are obvious reasons to pick the D, including the fact that it is (nearly) completely grade-separated.
There are lots of good reasons why it would make sense to extend the Blue Line to Riverside. Unfortunately, there is one very good reason against doing so, and to understand it, we need to take about two steps back and look at the bigger picture.
Northeast Corridor capacity along the Southwest Corridor
Railroad tracks into downtown are like pipes. They need to be able to feed all of the branches they go out to, and likewise they need to be able to accept all of the trains coming in from each branchline.
So we need to turn our attention to the mainline tracks on the Southwest Corridor, which ironically is also sometimes called the Northeast Corridor — southwest of downtown Boston, northeast of the rest of the country. There are three mainline tracks running from Forest Hills to Back Bay, which need to serve:
Commuter rail to Franklin and beyond
Commuter rail to Foxboro
Commuter rail to Providence and South County
Commuter rail to Stoughton, and eventually Fall River and New Bedford
Amtrak to New York and beyond
Commuter rail to Needham
As you can see, one of these things is not like the other. The Needham Line is the shortest commuter rail line after the Fairmount Line, it only serves two municipalities, and shares origins with the D Line, both being built from the remnants of some of the region’s oldest railroads. (If you’ve ever wondered why inbound Needham Line trains start their journey by going away from Boston, that’s why.)
You’ll notice that the list above includes some destinations that are future-state, including South Coast Rail, as well as expanded Amtrak service. The NEC is going to need more capacity, and there isn’t room to build more north of Forest Hills. That means diverting trains away. Franklin and Foxboro can be diverted to the Fairmount Line (and leverage existing grade separation to boot), but the longer distances to Providence, South County, Fall River and New Bedford necessitate access to the high-speed non-stop trackage along the NEC.
Needham should get rapid transit
Moreover, sitting just under 11 miles outside of downtown, Needham clearly sits within “Rapid Transit Land”, along with the likes of Riverside, Braintree, Lynn, and Waltham (despite technically sitting outside of 128). The NEC should be reserved for high(er)-speed regional rail, and the Needham Line should be served by rapid transit.
For those unfamiliar, converting the Needham Line to rapid transit is usually envisioned by splitting it in two: an extension from Forest Hills to West Roxbury, and an extension from Newton Highlands to Needham. (Once again, everything old is new: these alignments in fact were the paths of the original railroads, when built 150 years ago; Riverside-Newton Highlands and Needham Junction-West Roxbury were cut-offs added in later on.)
So, the Needham Line needs to be converted to rapid transit, and the Needham section ought to be served by trains coming from Newton Highlands. Extending the Green Line to Needham is a well-known and widely-accepted proposal (at least in terms of its feasibility), and is yet another proposal that dates from the 1945 map. Needham Heights to Needham Junction is a good candidate for LRT — the stop spacing is good, the existing station footprints are conducive to light rail stops, and the surrounding density is on-par for what we might expect, similar to the villages in Newton to the north.
Needham can’t provide the Blue Line what it needs: grade separation
Okay, so what happens if the Blue Line eats the D Line? In that case, we would need to have the Blue Line extend down to Needham too, and that’s where we hit the Big Problem: grade separation.
HRT like the Blue Line basically always needs what we call “full grade separation.” Basically that means “no railroad crossings” — bridges and tunnels only. “Light rail” is “light” in part because its vehicles are light enough that they can (sometimes) stop quickly enough to avoid hitting a pedestrian, and because they could collide with an automobile (potentially) non-lethally. “Heavy rail” fails both of those tests: trains that are longer, heavier, and faster which cannot safely coexist with pedestrians and autos without major safety measures.
If you want to extend the Blue Line, you need to find a way to grade-separate the tracks. Whether going over or going under, that will add enormous cost in terms of both finances and likely in terms of disrupting the built environment of the villages. Those costs will be extremely hard to justify.
So, barring major changes to the community, the following things are all true:
The Northeast Corridor will need capacity freed up for expanded service to Providence, the South Coast, and other distant locations
The Needham Commuter Rail Line is the odd one out on the NEC, and the only one that can be feasibly removed from the Commuter Rail system altogether
The Needham Commuter Rail Line therefore needs to be converted to rapid transit
The Needham segment of the Needham Line needs to be converted to LRT specifically
A Needham LRT branch would need to be fed from Newton Highlands
Therefore, Newton Highlands must be served by LRT
Therefore, converting the Riverside Line to Blue Line HRT is not feasible due to foreclosing the possibility of service to Needham, thus limiting vitally-needed capacity on the Northeast Corridor
Blue to Watertown and Waltham
Watertown and Waltham create an interesting quandary. There is a large gap between the Worcester Line and the Fitchburg Line, in which Watertown sits, right next to Waltham – both moderately dense communities and employment centers in their own right. And if you draw a line directly west from Bowdoin station, you almost directly hit Watertown Square and then Brandeis head-on; you only need to shift that line up 7 degrees in order to hit Waltham Central Square. Whether from Kenmore, Kendall, or Central, it seems perfectly reasonable to extend the Blue Line to Watertown Square and then on to Waltham.
The immediate challenge with this is that there has never been a railroad ROW between Watertown and Allston. Complete greenfield subway projects are extremely rare – almost the entire MBTA is built on land where rails were laid or tunnels dug over 100 years ago. To build straight across Allston from Cambridge to Watertown would require a major political and financial investment. If support for such an investment could be marshalled, it would be transformative for the area. But it’s worth considering the alternatives; in my opinion, there are more achievable transit solutions for both communities.
A combination of these services resurrected would be significantly easier to build than a brand-new HRT line, and would offer reasonable service with increased flexibility at much lower cost. The ROW of the Watertown Branch is largely intact, and would be an easy and natural extension of GLX’s Union Square branch; LRT would offer greater flexibility for grade separation and limited street-running, if needed. Newton Corner can be rebuilt and served by frequent electrified regional rail service and feeder bus service. And infrastructure investments along the 57’s corridor can increase reliability of service and lay the groundwork for eventual return of light rail service.
It’s also worth comparing ridership on the 70 (between Watertown and Central) and the 71 (between Watertown and Harvard): along the stretches between Watertown and the respective Red Line transfer station, the 71 saw over 1500 boardings compared to the 985 boardings on the 70 (not including boardings from Watertown Square on either, although the 71 performs stronger there as well). The 70 corridor is itself not crying out for rapid transit; its main appeal is its directness, and a frequent regional rail service from Newton Corner will likely be just as fast. It is true that, from Watertown Square itself, a Newton Corner transfer hub will be less convenient; but for any riders coming from outside of Watertown Square, it will just be a matter of riding a couple extra minutes on a feeder service.
Readers of the Wikipedia article on the Watertown Branch will note that it used to run all the way from Watertown Square to Waltham Central Square. Why not run the Blue Line to Watertown via the B&A ROW (with a short hop between Newton Corner and Watertown Square), and then follow the old ROW to Waltham? The problem is that the ROW really isn’t intact west of Watertown Square. Even for LRT, it’s very curvy and crosses streets at odd angles.
Again, for HRT, you would need to grade separate the route, which means subway, elevated, or lots of embankments with short bridges over streets. None of those would be popular in the suburbs, especially when rail has been gone for generations (unlike in East Watertown, where trains ran as recently as the 2010s).
Waltham is also much better served by the Fitchburg ROW – whether by frequent regional rail, an HRT extension of the Red Line from Alewife, an LRT extension of the Green Line from Union Square, or some combination of the above. And if you really wanted a rail connection between Waltham and Watertown, LRT would win out again, as you could look at lane-taking on Route 20 to do protected-street-running – again, not an option with HRT at all.
Blue to Brookline, Longwood, and points south
I’ve discussed above how an extension of the Blue Line to Riverside via Newton Highlands creates challenges. However, a partial extension could be more viable. Assuming a D-to-E connection is built, allowing D Line trains to run into Huntington Ave, an extended Blue Line could take over the ROW between Kenmore and Brookline Village.
This would require some clever tunneling underneath the Mass Pike to hook into the D branch – currently the D shares tracks with the C on the approach to Kenmore, so you would need to find an alternate route. But aside from that, this would probably be a relatively straightforward extension, as the ROW is already grade-separated. This would also have the significant benefit of providing HRT service to Longwood, a major employment center that is notoriously difficult to serve with transit.
One downside is that you would lose some operational flexibility on the Green Line. The trade-off would need to be studied to get a clear cost-benefit analysis, but I personally think the trade-off could be a reasonable one. An HRT link between LRT stations at Kenmore and Brookline Village could also provide benefit to a larger LRT network overall, depending on final design.
The other downside is that I think this alignment produces a dead-end. Once at Brookline Village, you can’t continue west, for reasons explained above. You could continue south toward Forest Hills, along South Huntington or the Jamaicaway, but at that point you begin to duplicate Orange Line service, at the expense of a lot of tunneling along an environmentally sensitive stretch of greenspace.
If you wanted to go for the moonshot, you could abandon the southern half of the ROW, and turn east at Longwood to tunnel directly underneath the LMA, potentially continuing further to Ruggles, Nubian, and points east and/or south – essentially building the southern half of the Urban Ring. This extension would require an enormous capital investment, though would likely also see enormous ridership.
In my next and final post on this topic, I will discuss why I believe the Kenmore alignment is the stronger choice, and what I think this choice represents for the system overall.