I want to turn to a slightly nitty-gritty topic, by way of some (over)simplifying abstraction.
There are lots of open questions about what could be done, transit-wise, in Chelsea. Does SL3 get extended? Do we build an Urban Ring? Is Regional Rail electrified and run through the NSRL? What kind of enhancements to radial service on the T111 and T116 are possible?
That all being said, we can be reasonably sure that, whatever gets built, it will fall into one of four corridors:
- T111 (Washington Ave)
- T116 (Broadway)
- a "Circle" Line
- Regional Rail
Looking something like this:
View attachment 46152
Even the most "out there" crazy transit pitch would only add one other potential corridor, along Route 1 (i.e. a heavy rail extension):
View attachment 46153
But for the most part, we're talking about those first four. Whether it's just high-frequency buses or full-out dual LRT lines, Washington and Broadway will both remain the major radial corridors, and the Grand Junction + Eastern Route is always going to be the main corridor running east-west.
So, my point is that the details of those implementations can be somewhat abstracted away.
Which brings up the nitty-gritty question: if the major corridors are over there to the east (circled in black), why have the Regional Rail station all the way the west (marked with the purple dot)?
View attachment 46154
Well, for one thing, you have to fit a platform. The old Chelsea station, to the west of Washington Ave, had short platforms (one of which is still partially extant) which couldn't be extended:
View attachment 46155
This means there are two questions here:
1)
Should the Regional Rail station be relocated closer to the T111 and T116 corridors? Does that answer change with NSRL through-running?
2) If so, is there
space for a relocated station, and if so, where?
On the question of space: looking at the (new) current Chelsea station, as well as the new center-platform Boston Landing station, a 2-track mainline station requires about 45 feet of ROW width. The tracks alone require about 30 feet of width. Rapid transit tracks require about 25 feet of width; the GLX stations require 45 feet of width (the GLX + Lowell total width is about 63 feet, by my measurements).
- Mainline 2 tracks: 30 feet
- Mainline 2 tracks + platform: 45 feet
- Rapid transit 2 tracks: 25 feet
- Rapid transit 2 tracks + platform: 45 feet
If a mainline station and rapid transit station are placed side-by-side, the ROW would probably need to be 90 feet wide. I don't really see any place within the circled area above that could accommodate that.
But, staggered stations might relieve some of the pressure to squeeze full-width stations side by side (75 feet at the rapid transit station, 70 feet at the mainline), something like this:
View attachment 46156
It looks to me that the ROW between Washington and Broadway is
just about 70 feet. The ROW to the west widens a bit to 80 feet (actually wider than that if you include the old mainline platform, but its spacing seems like it would be mostly useless for tracks and platforms), though lengthening the current SL3 station to GLX size might be a little more challenging.
(I see that
@F-Line to Dudley proposed
killing the grade crossing at Arlington & 6th entirely, which would free up more space for the LRT platform.)
Setting aside the silliness of making the brand new Chelsea station obsolete, this raises the larger question about the role of the Regional Rail stations, the Circle Line services, and the necessities of transfers to/from the T111 and T116.
My take is that it makes sense to relocate the mainline station to Washington / Broadway
after NSRL is built and mainline trains at Chelsea are through-run to South Station and beyond; at that point, being able to transfer from the T111 and T116 (a la Sullivan Square) becomes more valuable. Until then, mainline passengers who are commuting, e.g., Salem <> Airport can transfer to Circle services at the current Mystic Mall station.
Would frequent non-NSRL Regional Rail services tip the scales in favor of relocation? I still think probably not -- I don't see many T111 or T116 riders transferring to North Station-bound Regional Rail instead of riding to Haymarket or transferring at Maverick.