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Trolleys in crisis: MBTA says power wire on brand-new Green Line Extension failed 'prematurely;' older wires elsewhere failed because they can't deal with sudden shifts in weather

MBTA wire workers

They've been working on the wires, all the livelong day. Photo by MBTA.

The MBTA said yesterday it's identified the overhead power-line issues that have led to a recent spate of dead trolleys from the new Green Line Extension to the ancient tracks near Copley and on Beacon Street. The T also said it's working to keep them from happening again.

The first sudden end of service occurred Oct. 20 on the tracks between Science Park and Lechmere - leaving some riders trapped in a trolley for 90 minutes - on one of the MBTA's brand-spanking-newest lines. The T reports:

We found a broken OCS [overhead catenary system] cutout near Lechmere. Green Line Extension is a new "constant tension" system, using cables, pulleys, & weights to maintain the right amount of tension on the OCS power lines. We suspect this cutout failed prematurely & is an isolated case.

The other three failures - near Copley, also near Copley and on Beacon Street in Audubon Circle - were due to the fact that, hey, we have the nation's oldest subway system:

These were older parts in our legacy system - a "static tension" system that cannot self-adjust to tighten wires. We suspect the recent severe temperature swings caused the [wire system] to sag, wear, & break.

The T continues:

To avoid future power problems with our legacy system, we're looking into upgrading our inspection technology to new cameras & sensors to detect defects better. For now, our Power Dept is further inspecting our most sensitive Green Line sections & has replaced ~200ft of OCS wire.



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Simple fix: If they don't like the weather, wait a minute. Oh wait, that is the problem.

Voting closed 21

Move T to more stable climate.

Voting closed 36

Ok, look, the tracks are bad. The power wires are bad...The cars are bad...

Let's look on the bright side...let's make a list of all the things that are working correctly.

Ok, you go first.

Voting closed 51

At least, the new type-9s are pretty solid, easily the T's best procurement in decades.

On the red and orange? Not so much.

Voting closed 10

  1. The original tunnels haven't collapsed and the new trolleys work peachy keen underground!

That's about it.

Voting closed 4

The issues occurred between Oct 20 and Oct 25.

From October 6 to October 24, the temperature ranged between 45 and 71. That's a range of temperatures which Boston can experience in a single day (April 13 of this year: low of 49, high of 88).

Also, two of these occurrences were underground where the temperature barely varies at all.

But, sure, temperature.

Voting closed 57

The wires were old and that's what made them snap.

Thanks for reminding me of that April day. I planned a mid afternoon long run weeks before only to worry that I wouldn't make it to the end. Shouldn't be 88 in April!

Voting closed 11

but instead of fixing the antiquated system.. hey lets throw some technology at it to **detect** when it has an issue.

Hey I get it, early detection alerts them of problems before they happen but ya know... at some point it might be good just to fix the whole damn thing.

Still amazes me at all the talk about these Green Link Supercars (Type 10s) but little about fixing how antiquated the rails and electrical systems they will use. Its always "oh look shiny new things" vs infrastructure fixes that aren't sexy or shiny.

This also reeks of "slippery rail"

Voting closed 28

You'd still want early detection systems for issues to catch before they become real problems that impact service. New things still wear down, have defects, and can fail. Just look at the GLX - all brand new, and lots of problems.

As for the Type-10, they MBTA has pretty well detailed all of the power, station, and track upgrades needed in tandem with the new train sets needed to get things running. In the last few years, the T has replaced more track than it has since the 60s on the branches. The days, it's debatable at this point how much of it was done correctly given all the suspect stuff the went down during Baker.

Voting closed 13

The wires, too.

What's next? The ties?

Voting closed 14

So, they suspect the first problem is an isolated case--but they don't know, because they don't know what happened.

And they suspect that the other problems were all caused by the weather. But that's a guess, in part because they don't really know whether they all had the same cause.

Voting closed 8

They screwed up the track gauge and catenary wires, both visible and pretty basic things to get wrong.

So how f'd is all the other aspects of the extension which aren't visible? Was the concrete poured correctly? Is there some massive problem with the foundation that will require years of bussing once it becomes apparent?

Voting closed 14

I had the opportunity to ride the extension from Union Sq to Lechmere in August, but couldn't because of wire problems at Copley. The train sat there for half an hour before someone made an announcement. Thankfully, I was able to hop on the Route 91 bus to Sullivan.

The MBTA's attitude on GLX was to get much of it done without thinking about anything else, i.e. "let's get this built for the photo ops and the influx of high-income renters along GLX, and worry about everything else later."

Voting closed 10

A number of people have commented that the state/Baker/etc rushed the job.

But they kept missing deadlines! The project was years and years behind schedule. Even the actual opening date got revised many times.

I don't think it was a rush job. I think the contactors knew nothing mattered so they could take every shortcut and ignore every failure and screw up. It's as if they assigned their college interns to oversee the project.

Voting closed 17

the interns would have done a better job.

Voting closed 10