Re: 300 Mass Ave (Central Sq) Cambridge
The capacity of the red line is fine 90% or more of time. Morning crush will always happen, but people adjust their schedules to accommodate. Until the state is ready to build the Urban Ring rush hour is going to suck.
How short are you going to make headways? 2 minutes? Less? I think people will adjust their commuting pattern before demand ever gets that high.
Mixed-use development at all transit stops can help alleviate the crush in the near term and on into eternity. More jobs mixed into the largely residential outlying stops and more residences in the downtown core will get people moving in all directions or not needing transit at all if home and work are close enough to walk or bike.
Voila - "added capacity" during rush hour that doesn't cost the MBTA or riders a dime.
The problem with Red is that its old, pre-1988 wayside signal system allowed much tighter headways than today. When they installed the current ATO cab signals it was simultaneous with the introduction of 6-car trains replacing the former 4-car trains. The T incorrectly assumed that 6-car trains would swallow up the crowds so well that dwell times would be trivial forevermore, obviating the need for short signal blocks and letting them permanently relax the headways. Within 5 years flat the demand started overwhelming capacity, dwells at stations like Park with narrow platforms and egresses only on one side got WORSE with 6 cars than they were with 4, and those too-long downtown signal blocks became an escalating choke point. This is why why morning rush has nearly every train pausing on the Longfellow and crawling to Park, and PM rush has so many trains holding at Broadway, SS, and DTX for schedule corrections.
It all used to work, but has been artificially crippled for 25 years. They have to fix what they broke. They CAN fix what they broke without needing to consider boondoggle solutions like excavating 8-car platforms in every station to slam into the same choke points. Now, they don't have to do 2-minute headways if they don't want. NYC Subway so far has only installed CBTC on a few stub-end shuttle lines that never see that much traffic. But the advantage of that system is that it's 2-way, higher-bandwidth communication between train and signal system that doesn't rely on fixed blocks hard-wired into the trackside hardware. The current system can only bark STOP or levy a unilateral speed penalty at a block. It's all-or-nothing. CBTC can do moving blocks with the live 2-way computers self-correcting for choke points so you don't have to have aggravating dead stops in the tunnel anymore...you can just hold back a few MPH from Harvard to Central to Kendall until the next train ahead that's departing Kendall behind schedule catches back up to proper train spacing. This saves those "hold for schedule adjustment" gaps where the Central platform gets dangerously overcrowded. That's immediate gains in schedule resiliency and dramatic reduction in delays even if they buy not one more car to do 1 second's better avg. headway. It'll seem like much better headways simply by closing up the gaps and eliminating those mind-numbing pauses for bunching.
It's also adaptable vs. frozen in time. If they don't want to buy more cars or upgrade the power system now, it'll cost a lot less to do just signals and still reap the OTP benefits of the new system. But if they want to tighten headways later, they can just reprogram the computer for tighter moving blocks instead of being stuck for 25 years with fixed capacity that can only be modified with $$$ and labor.
I do think that flushing headways tighter does more overall for the overcrowding than any other single solution. They still need Red-Blue and a Green-SS/Seaport link to relieve loads because those Park and DTX platform dwells can't be allowed to get any worse. Not even a signal system is going to save the Park platforms from getting so overstuffed right up to the yellow safety line that it takes 5 minutes for the crowds to reach the stairs. But any way you slice it Red's still going to be the biggest load-bearing backbone of them all. And it's not firing on all cylinders today with its decaying condition and self-induced flow mistakes. Fix it now and it still has lots of room to grow.
