I seriously hope someone makes a FOIA request on their communications related to the shutdown and the persistent slow zones. Might be the only way the real truth comes out, much like with the Blue Line tunnel closure fiasco.
In related news, North Station to Assembly northbound is finally back to pre-shutdown levels. The caveat there is that this stretch, especially between North Station and Community College, was a brutal ~3 minute slow zone before the shutdown began. So there's still 3 minutes of slow zone left to remove before they can even get this stretch to the old status quo, never mind anything that truly is "faster service".
Unfortunately, they appear to have made absolutely no progress southbound.
Elsewhere on the line...
Wellington to Malden Center northbound is still over a minute above pre-shutdown levels.
Tufts to Chinatown northbound is nearly a minute above pre-shutdown levels. Southbound, Chinatown to Tufts is over 30 seconds slower. It's such a short distance, but these graphs are still embarrassing for the MBTA.
Tufts to Back Bay in both directions looks like child's play now compared to the Assembly to North Station slow zones. However, I decided to do some longer-term investigation of the stretch and the results were damning.
Southbound, Tufts to Back Bay is still running at ~2.4 to 2.5 minutes. This is a bit faster than pre-shutdown and quite a bit faster than earlier this year when it ran over 3 minutes, but slower than a brief period in late July.
I decided to go way back and see how this section ran in the early days of the TM tracker..... for a large part of 2016 and 2017 it ran at just 45 seconds. I have so many questions as to how it got as bad as it did.... yay for deferred maintenance.
Going northbound, travel times have improved by over 30 seconds compared to pre-shutdown from 2 minutes to just under 1.5 minutes.
Extending the graph out, the area is still running a bit above where it was for much of 2021 (about 1.25 minutes):
Doing the same long-term analysis for the northbound direction as I did for the southbound direction, I can only find travel times as low as about 1.1 minutes, dating back to early-mid 2016 (see screenshot below). (However, for much of 2018, much of 2019, and around half of 2020, times were just so slightly higher at 1.2 minutes.)
Does anyone with more expertise about the design speeds in this area know if Back Bay to Tufts northbound is just designed for a lower speed in general? Regardless of the current issues, I would expect there to be at least some stretch of time where trains could traverse it in ~45 seconds, so either the design speed is lower going northbound or there is a super long term slow zone of sorts going northbound.
Either way, it's downright ridiculous that it ever got to the point where long term slow zones are even a thing. It's almost like their strategy to fix aging track was to just institute slow zones. It's a shame that this technology wasn't around when, say, the SWC opened, as I would be very interested to look at BBY-Tufts data from when it opened.