Green Line Extension to Medford & Union Sq

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I’m setting the over/under at a three month delay for the Medford Branch opening due to the asbestos remediation near the High School. Does anyone want to take the under?
 
RandomWalk said:
I’m setting the over/under at a three month delay for the Medford Branch opening due to the asbestos remediation near the High School. Does anyone want to take the under?
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What part of the critical path do you see that impacting?
 
RandomWalk said:
I’m setting the over/under at a three month delay for the Medford Branch opening due to the asbestos remediation near the High School. Does anyone want to take the under?
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What is the net opening date before your delay and after?
 
Does anyone have any insight as to why the E branch was chosen to run on this extension at all? I recall the reasoning for D to Union and E to Medford being that E was shorter. With the E branch running in mixed traffic on the other end of its line, it seems like the Medford branch will be plagued by bunching, delays, etc. I assume B or C with full signal priority would be more reliable.

It seems like billions invested in fully grade separated transit and 60 mph tracks on one end of the line are a bit wasted when the other end is 5mph in mixed traffic.
 
Badusername said:
Does anyone have any insight as to why the E branch was chosen to run on this extension at all? I recall the reasoning for D to Union and E to Medford being that E was shorter. With the E branch running in mixed traffic on the other end of its line, it seems like the Medford branch will be plagued by bunching, delays, etc. I assume B or C with full signal priority would be more reliable.

It seems like billions invested in fully grade separated transit and 60 mph tracks on one end of the line are a bit wasted when the other end is 5mph in mixed traffic.
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It's been discussed on here before but I think the primary reason is reducing the number of people who need to change trains, D&E have the most OD pairs with riders on the extension.

Also purely speculation but I think having the E run to a terminus could help it's headway management compared to turning at govt center. The lines that turn at government center have to start their outbound trips pretty much immediately, so any uneven headways are compounded. Running to the terminus allows them more ability to space the trains as they send them out.
 
Badusername said:
Does anyone have any insight as to why the E branch was chosen to run on this extension at all? I recall the reasoning for D to Union and E to Medford being that E was shorter. With the E branch running in mixed traffic on the other end of its line, it seems like the Medford branch will be plagued by bunching, delays, etc. I assume B or C with full signal priority would be more reliable.

It seems like billions invested in fully grade separated transit and 60 mph tracks on one end of the line are a bit wasted when the other end is 5mph in mixed traffic.
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Here's the official reason:
The specific branch assignments are a reversal from earlier plans, which called for extending the D branch to Medford and the E branch to Union Square. Asked about the switch, Pesaturo said Friday that the D branch — which is by far the longest arm of the four Green Line branches — was assigned to the shorter extension to Union Square to make it a more reasonable length for trains.

“A shorter trip than the D branch, E branch trains have been assigned to the longer leg of the extension (Medford),” Pesaturo said in an email.
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Edit: Another reason why the D and E branches were chosen, but not B and C, was that they serve Longwood:

Pesaturo noted that those two branches serve the Longwood Medical Area, and this will minimizing transfers for riders who take the commuter rail to North Station, as well as the Green Line Extension.
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Badusername said:
Does anyone have any insight as to why the E branch was chosen to run on this extension at all? I recall the reasoning for D to Union and E to Medford being that E was shorter. With the E branch running in mixed traffic on the other end of its line, it seems like the Medford branch will be plagued by bunching, delays, etc. I assume B or C with full signal priority would be more reliable.

It seems like billions invested in fully grade separated transit and 60 mph tracks on one end of the line are a bit wasted when the other end is 5mph in mixed traffic.
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Well, the T has always seemed to have an irrational hatred for the street running portion of the E, maybe they think if they argue it's screwing up the GLX they'd finally be able to get rid of it 🙃

HelloBostonHi said:
It's been discussed on here before but I think the primary reason is reducing the number of people who need to change trains, D&E have the most OD pairs with riders on the extension.

Also purely speculation but I think having the E run to a terminus could help it's headway management compared to turning at govt center. The lines that turn at government center have to start their outbound trips pretty much immediately, so any uneven headways are compounded. Running to the terminus allows them more ability to space the trains as they send them out.
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I agree that turning the E in particular at GC was probably not something they wanted, though I don't believe that GC has ever been a significant turnaround point for that branch (which generally ran Heath-Lechmere, layered with Arborway-Park before the "temporary" suspension).

It's also worth noting that the E's the only branch without any meaningful yard space on it (Cleveland Circle's direct-adjacent to Reservoir), which is part of why it was perma-stapled to Lechmere and its yard (though they still tended to store additional cars off-peak on the Brattle Loop every now and then). With the E being a GLX branch it's now directly connected to the new maintenance facility and storage yard replacing Lechmere's capacity. Does cut down the need to shuttle trains in off the other branches for the Huntington service.
 
My understanding:
B and C were the most bunching prone and are already fairly long operator shifts
The D and the E were more likely to be unbunched.
 
HelloBostonHi said:
The E branch is eternally bunched.
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D branch is moderately better
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But neither are anything close to consistent compared to the Blue Line
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What could / is the T doing to reduce this bunching? Transit signal priority seems like an obvious one, but this article mentions software that was piloted on the D branch in 2017 to reduce bunching: https://commonwealthmagazine.org/transportation/t-trying-to-speed-up-green-line-trains/

Interested to know if anyone knows if this software was ever implemented and if headway management is trending any better.
 
So what letter will the new GLX line be given to the very end of it? I'm thinking maybe F. All the letters before that are already taken. :unsure:
 
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