BostonUrbEx wrote:I'm not talking about the tunnel in general. I know why the tunnel had to exist because FRA, Orange Line, etc. That topic has been hashed out a million times.
There's still a ROW the exists, I'm not exactly sure what its condition is, that bypasses the tunnel. I believe it might only be a siding that also branches off to the Stoneham branch. But if freight was going to pass through the area, there's totally a way to bypass the tunnel.
I'm strictly asking about why the commuter rail was placed in a tunnel not designed for commuter rail. There was never any intention of routing the commuter rail through that tunnel when it was designed and built. It was an after-thought and then they had to raise the ceiling to modify it for commuter rail service. At what time was this tunnel modification made and the commuter rail shifted into it's current location? Allowing for less restrictive freight ops does make sense, but depending on when this shift was actually made, it might not truly have been necessary?
The surface siding re-connects to the main, but one of the switches is out-of-service. Or at least was OOS for the longest time. It's a bona fide proposal to rebuild that thing as a commuter rail passing track, since one is badly needed in the area. It's just not a funding priority because the rest of the Haverhill Line upgrades up north are running years late, and Town of Plaistow killing the past-Haverhill extension has put the T in a bit of lurch for finding a replacement layover yard for cramped Bradford. Can't increase the schedules much without replacing Bradford. There's still one site on the Haverhill side of the state line that was Alternative #3 for a Plaistow layover yard and still in-play for the T as a Bradford relocation, but it's unclear after the collapse of the Plaistow extension how practical that's going to be. They wouldn't do this passing track in Medford without some sort of schedule expansion to hang its hat on, and schedule expansion is dependent on the layover situation.
As for why it wasn't used...B&M still had dense enough freight in 1975 when the new track configuration opened for Orange that it got priority over the surface route. Obviously not needed anymore, but I think there's some paper formality that still has to be executed to retire that freight priority. As well as fixing the OOS north switch and just refreshing the infrastructure in general. The tunnel enlargement was simply a last-minute design change when the Reading extension of Orange got canceled.
That doesn't fix the clearance restrictions, though. They can take Plate F cars down the Lowell Line (incl. after GLX construction fixes a couple of the clearances it 'breaks' in the course of building the Green Line); it's a protected clearance route, which is why it's PAR's preferred route that they hate deviating from. They can't take large cars down the inner Fitchburg or Reading because of the high platforms at some stations and the more limited undergrade clearance. That's what's forcing this limitation, not the tunnel; a Medford Branch job would never use the tunnel to begin with.