Green Line Extension to Medford & Union Sq

The MBTA replaced all the track on the Lechmere Viaduct in June 2023 after the track “renewal” work conducted in 2021 was ineffective. There’s really no excuse why trains still run 10mph after they literally replaced the rails and any “settling” period has surely elapsed.
 
Not.... not good.
The T shut down train service on the entire Green Line extension Friday afternoon and forced some riders to walk along the tracks after a problem with the overhead electrical system, according to a tweet from the agency and a reporter who was among the passengers on a stalled train eventually asked to proceed on foot.
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www.bostonglobe.com

Green Line Extension was shut for four hours because of new problem on Friday - The Boston Globe

The extraordinary scene came a day after general manager Phillip Eng revealed widespread track problems on the newest part of the T’s subway system.
www.bostonglobe.com www.bostonglobe.com
 
Then read THIS. It's part of the growing concern about workers getting hurt on the Red Line as well as everywhere else on the property!! :eek:

 
Listening today to the T's board meeting, it appears that the ties were delivered to the T with the tie plates preinstalled. Evidently, they came from the tie supplier too tight, and the rail was simply installed on top of that. Eng believes that it was a fabrication issue, given the widespread nature of the defect, which wasn't addressed on delivery hence the firings. Currently, GLX constructors is thinking 10-14 days of early access (9-5am) closures to address it.
 
Stlin said:
Listening today to the T's board meeting, it appears that the ties were delivered to the T with the tie plates preinstalled. Evidently, they came from the tie supplier too tight, and the rail was simply installed on top of that. Eng believes that it was a fabrication issue, given the widespread nature of the defect, which wasn't addressed on delivery hence the firings. Currently, GLX constructors is thinking 10-14 days of early access (9-5am) closures to address it.
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I have been guessing that was the issue because of the prevalence of the problem.

You have a supplier installing the plates on the ties. That installation process is almost certainly fixtured to speed up the process (and ensure consistency). Someone sets the fixture at the wrong width, and it does not get caught. Supplier cranks out thousands of bad ties with plates. Not catching that on incoming supplier QC inspection at the work site is a fireable offense. (Or potentially worse, catching the error and still allowing the ties to be installed anyway because must hurry up for Baker's photo op!)
 
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How will this be fixed? Do the plates have to be moved on all the ties impacted by this error?
 
NHMaples said:
How will this be fixed? Do the plates have to be moved on all the ties impacted by this error?
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  1. Pull up spikes on one side.
  2. Shoot quick-dry epoxy into spike holes.
  3. Epoxy hardens.
  4. Reposition tieplates.
  5. Spike repositioned tieplates.
That's supposedly the way it goes when there's been a spiking error. It's all automated with machinery.


EDIT: Here's some examples of the types of track critters they'd use for this, with videos showing them doing their thing. . .

Spike puller (machine that pulls the spikes) https://en.wikipedia.org/wiki/Spike_puller
Tie plugger (the machine that dispenses the hole-plugging epoxy): https://www.sperlingrailway.com/RailwayProducts.php?Ride-On-Tie-Plugger-62
Plate layer (the machine that positions the tieplates): https://www.sperlingrailway.com/RailwayProducts.php?PL-4-Plate-Laying-Machine-59
Tie driller (drills the new spike holes): https://www.sperlingrailway.com/RailwayProducts.php?QUADRILL-5
Spike-driver (installs the spikes): https://en.wikipedia.org/wiki/Spike_driver

The machines would also be configured to lift up/out the rail they're replacing the tieplates on. And some machines may combine the functions listed ^above^.
 
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F-Line to Dudley said:
Tie plugger (the machine that dispenses the hole-plugging epoxy): https://www.sperlingrailway.com/RailwayProducts.php?Ride-On-Tie-Plugger-62
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Wow that's an enormous vehicle for a tiny epoxy spout
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The video almost looks like a person is moving the nozzle manually, which would be serious overkill.
 
Koopzilla24 said:
In a live streamed announcement by Eng a couple hours ago he stated that 56 1/8” is their minimum tolerance for being “restricted gauge” meaning it needs to be addressed. So the rails can be up to 3/8” too narrow before a speed restriction is imposed.
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Listened in to the board meeting and what I have here is incorrect. Eng clarified that 56 1/8" was the minimum track width found and what caused the sudden speed restrictions. The MBTA has a tolerance of 1/16" which was stated to be much more strict than the industry standard. The rails that exceeded this tolerance were in the range of 56 1/8" - 56 7/16".

In short, the most narrow rails discovered had a gauge of 56 1/8", five times the tolerance limit, but still a tiny fraction of an inch.
 
Koopzilla24 said:
Listened in to the board meeting and what I have here is incorrect. Eng clarified that 56 1/8" was the minimum track width found and what caused the sudden speed restrictions. The MBTA has a tolerance of 1/16" which was stated to be much more strict than the industry standard. The rails that exceeded this tolerance were in the range of 56 1/8" - 56 7/16".

In short, the most narrow rails discovered had a gauge of 56 1/8", five times the tolerance limit, but still a tiny fraction of an inch.
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Yeah, but we have those wonderful Type 8 cars, that derail at the sight of a mouse hair on the track.
 
Koopzilla24 said:
Listened in to the board meeting and what I have here is incorrect. Eng clarified that 56 1/8" was the minimum track width found and what caused the sudden speed restrictions. The MBTA has a tolerance of 1/16" which was stated to be much more strict than the industry standard. The rails that exceeded this tolerance were in the range of 56 1/8" - 56 7/16".

In short, the most narrow rails discovered had a gauge of 56 1/8", five times the tolerance limit, but still a tiny fraction of an inch.
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More accurately, the construction tolerance specified for GLX is 1/16" from the design gauge. That's what the T is supposed to receive from GLX constructors, so that new track is supposed to be in perfect "as designed" condition - that's why they're on the hook to bring the track to the standard of ±1/16".

The acceptable gauge for the GL generally for operations (with or without slow zones) is a bit wider than that - from a minimum of 56-3/16" to a max of 57-3/8" - see previous post below for published specs. 56-1/8" is outside of the "known" operational range requiring walking pace ops.
Stlin said:
The MBTA does actually publish it's standards for most everything under the "Engineering" section of their website, be it station canopies, track turnouts, etc. The relevant section of the Green Line track geometry standards (PDF) are under the maintenance tab. [Snip].
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GLX repair work and Lechmere Viaduct repair work to run from November 27th to December 22nd as early access work. This work will coincide with the Government Center Garage demolition. It will also complete the lifting of the Lechmere Viaduct speed restriction.
 
Delvin4519 said:
GLX repair work and Lechmere Viaduct repair work to run from November 27th to December 22nd as early access work. This work will coincide with the Government Center Garage demolition. It will also complete the lifting of the Lechmere Viaduct speed restriction.
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Not to disparage the hard work under adverse conditions that I'm sure everyone at the T is doing, but we've heard this one before.
 
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