The fancy new two-car trains will be “limited,” with most pulled from the fleet for more repairs, so expect more crammed commutes in the short run.  

The litany of liabilities with the ultramodern new Muni light-rail trains has memorably included such problems as doors trapping and dragging an elderly woman and coupler failures causing the double car trains to detach from one another. We were then warned Thursday to expect packed and problematic commutes, as much of the new $1.2 billion fleet was being sidelined again, though Muni was pretty scant on details explaining why. That led some of San Francisco’s top train-chasing gumshoes to investigate why the trains were pulled, and they’ve found answers that are of course embarrassing to Muni and the trains’ manufacturer Siemens. The San Francisco Examiner found that in a Wednesday night K-Ingleside incident, double-car trains detached and rammed into each other, and NBC Bay Area reports that the shear pins that hold double-cars together are failing.

Wednesday night’s discovery of the problem was thankfully an isolated incident with no known injuries, but one that clearly affects all 68 new trains in the fleet. A memo obtained by the Examiner, seen above, details that “the coupler shear pins failed on one of our LRV4 trains while in revenue service,” but claims “the cars did not separate.” (This interpretation may depend on one’s definition of “separate.”) The memo says that “the operator reported to her Supervisor that it felt like her train was being continually rear ended.”

The shear pins were found to be failing around three months into service, as the Chronicle reported Thursday. The SFMTA assures us that in the next round of new trains to be delivered in 2021, they expect the issue to be resolved so that the pins don't need such frequent replacement.

The Examiner was later informed that a “runaway train” situation is impossible, during a Muni damage control train yard press conference that’s becoming an all-too frequent occurrence since these new trains were rolled out. The trains are supposedly programmed to stop automatically if they come loose from their lead double-car.

But needless to say, this is trouble for the manufacturer Siemens. The Board of Supervisors has threatened to withhold future payments for the repeatedly faulty cars. Never at a loss for words, Sup. Aaron Peskin told NBC Bay Area that “We are now back to square one. I want to know who knew what, when," and added, "We are going to ask the tough questions, we’re going to get answers and if this is not ready for prime time, we’re not going to fund it."

In terms of this evening’s commute, expect it to be bad. The memo obtained by the Examiner details that Muni will “operate only three (3) two-car trains” of the new variety this evening, with a handful more supposedly to be back on the tracks by Monday. But expect the worst, because it is an unlucky Friday the 13th, just like the day these cursed new trains were rolled out.

Related: Rainstorm Floods Muni and Multiple Corners of San Francisco [SFist]

Image: Nathan Y via Flickr