Simmer down kids, its not that hard a concept.
High level light rail (either electric or diesel) is superior to green line trains because of true level boarding + no space wasted on interior stairs. Also, smoother ride.
Irrelevant, because you can't get there from a level-boarding route. They ruled the Blue Line wraparound alternative as too hard to construct over 10 years ago. It's run as part of the Green Line network, so if there's going to be surface branches there has to be low boarding platforms. There's no parallel universe where we can cleanroom this thing, so that's just impotent postulating about something that can never happen.
Also: wrong, wrong, wrong on diesel and mainline RR DMU's. They're slower, heavier, and less nimble--anywhere in the world--than a rapid-transit car or trolley. Do not even try to fling this BS out there if you're not willing to offer any supporting data whatsoever. I want just one person in this thread who's lazily clinking to the "DMU's: the New BRT-ish Wonder Drug!" talking points to substantiate that with something.
It's been documented to the nines for decades that 15-minute headways are the most they can swing on shared commuter rail tracks. Dispatching is contingent on what the terminal district mash-up can bear. It doesn't matter where the GLX dinky peels off...North Station or this convoluted GC fantasy that doesn't have the clearances or weight limits to ever support it to begin with. If it interacts with any Lowell Line slots during the service day, it's going to be capped at 15. This isn't a hermetically-sealed operation like the RiverLINE under DMU's; it can't be if it's on the Lowell tracks. The hermetically-sealed operation we're building is GLX. Which goes to GC. So why in the hell is diesel even being mentioned except for pointless deflection?
Don't personally believe any of that...provide some evidence instead of fact-free snark.
For the new stations, the concept is simple - build them high level platforms from the start.
Answer all of the above, because this is irrelevant until you prove how you're going to get high-level cars there in the first place...on what mode...with that mode meeting the frequencies mandated by the project.
For lechmere, north station and haymarket, you would have half the platform be low level, half be high level. Haymarket and North Station are already about 57 train cars long, so it is very possible. The new Lechmere would be built with this in mind.
So you're going to save money by making the stations twice as expensive, add multiple NEW station mods to the project budget when the whole point of this ongoing sidebar is "the project is too expensive...it needs a less-expensive substitute!"...and cut capacity so no other trains can load back-to-back on the platforms. Haymarket is not "57 train cars long". You will no longer be able to board back-to-back trains in the station with a modification, which cuts headways on the Green Line writ-large because fewer branch schedules will be able to poke out there. All of the slack space for that on the other side of the wall in the pre-1971 station was eaten up by the new track curve into North Station. North Station's and Lechmere's platform lengths--and the contradictory budget premium you're spending on them--become irrelevant with Haymarket being the limiter.
What does that do to service? Right now Haymarket-Lechmere Station is slated to gain +1 branch's headways with GLX as the D joins the C & E to North Station and E through Science Park + Lechmere. 6-minute headways per each branch at peak. Cripple Haymarket's ability to load back-to-back and you eat those gains by sacrificing the additional 6-minute frequency branch schedule in favor of the pants-on-head high-level dinky's 15-minute maximum headway. Oh, and also tack on some additional loss of headway to Lechmere on top of that because of extra dispatching buffer needed to thread two branches' 6-minute headways with slotting from the Frankenstein dinky's mismatched 15-minute headways. Glorious mess!
EXACTLY. SO WHY ARE YOU PROPOSING SHIT YOU CAN'T DO AS A SO-CALLED "SOLUTION"?
Words in posting field! So many words on this last page-plus with so little to say!
Except its a proven concept in Cleveland.
Explain what the fuck Cleveland has to do with the infrastructure in Boston? Comparing Oranges to kumquats proves nothing.
Thats where Brattle Loop comes in. The new Somerville line would terminate in Gvt Center using the loop. The loop itself would be designed for high doors, so no need to share.
Explain how you do this with all of the other constraints actively harming headways and driving up the budget for...reasons?
Operationally, this is important, because a car on the tracks in Brighton wont fuck over service in Somerville. It is easier to manage two entirely separate lines than trying to throw in more branches
No...the car on the tracks in Haymarket fucks over the cars in Brighton. Which is so much better because unsupported Internet argument.
