from https://archboston.com/community/threads/crazy-transit-pitches.3664/page-276#post-464359
I have no clue if this would work, and as outlined in the linked thesis there would need to be additional modifications to the curves to reach a 66-foot radius, but my general thinking was:
Current northbound Brattle Loop track is abandoned and/or converted to storage — abandoned bits in red, potential storage/ancillary track in grey.
Southbound Brattle Loop track (on the western side of the loop, shown in “forest green”) is flipped to run northbound, and a new curve of track (light green) at the north end connects to the northbound track just outside of Haymarket. At the opposite end, it runs into the reopened second platform and ends in a stub.
The often-photographed in-station curve is abandoned and filled in with a platform. This provides access to the second platform without needing to cross tracks.
A new crossover between the outer southbound track and the west side Brattle Loop track provides access to the stub platform for southbound trains.
Much more speculative is slotting a second track along the second platform, in order to avoid creating bottlenecks — marked with a dashed line because it’s so speculative. I suppose that’s a possible use for the otherwise abandoned east side Brattle Loop track — rework the switches to provide access from the southbound track at Haymarket, and take turning trains out of service at Haymarket… not ideal but.
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After sketching up all that, I found this: https://web.archive.org/web/2016120…ects_List/Gov Center Station Presentation.pdf
Page 19 has this:
Which I then doctored into this:
The crossover in red is mandatory, although it doesn’t have to be in that specific location. The second orange track, as well as the short extension of the extant track, are optional — the second track both requires expanding the footprint of the station and potentially would require too sharp of a curve, thus negating the benefit of the entire exercise.
The tangent stretch of the west side of the Brattle Loop should be enough to berth one T10 car (at 114′); you could maybe fit a pair of T10s by lengthening the track, but that would require more significant modification to the station in order to avoid the elevators etc.
But yeah, I really don’t know. IIRC, F-Line once had an interesting idea for quad-tracking GC station, which would certainly be ambitious.
Actually, I suppose if you can figure out a dual crossover at Haymarket, you could turn both legs of the Loop into tangent tracks and point them inward toward the core of the station: