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What's Frying the Electrical Systems On BART Trains? (ieee.org)
Tekla Perry writes: Earlier this month, BART engineers shut down a substation in hopes that the closure would quiet the power surges that were frying the electrical propulsion equipment on BART cars -- a peak of 40 in just one day in February. The shutdown seemed to solve the problem, but BART officials weren't sure they'd really found the answer. Yesterday, the power surges popped up again, on an entirely different section of tracks, damaging 50 cars before BART closed off that section, rerouting passengers onto buses. Track inspections yesterday revealed nothing, and BART reports that it has reached out to experts around the country and asked them to fly in and help solve the mystery. Do you have a theory? Note: BART is the 5th-busiest heavy-rail rapid transit system in the U.S.
BART already tweeted the reason behind the breakdowns:
From @SFBART:
BART was built to transport far fewer people, and much of our system has reached the end of its useful life. This is our reality.
BART has been continually expanding while deferring maintenance on the rest of the system, and that policy has finally come home to roost -- much of their infrastructure is over 40 years old and they can't defer maintenance forever. But by continually expanding, they've made themselves too big to fail (and they've gotten more counties on the hook to keep the service running), so they'll get bailed out one way or another.
So the A & B cars having inductions motors seem to be fine, while the problem seems to be confined to the C cars having the DC motor. That's one difference.
Also, what else has changed? Take a look at wunderground to see that the Bay Area is having a wet season.
Why would the C cars have been mostly fine all along and having trouble now?
So there's charge building up in the DC motors that they can't handle and that makes them blow out. The charge has nowhere to go. What controls the flow of charge? Grounding. What can go wrong with grounding? Good grounds can go bad when a lot of discharge causes the sand in the soil to vitrify (melt into glass) after discharges and lightning strikes have been shooting through it for decades. Better grounds can unexpectedly form when more highly conductive paths form up. The AC induction motors will suffer a power loss but can handle the charge jumping back & forth in unexpected ways, while the DC motors can't.
Add it all up. This has to be a grounding problem aggravated by the wet season, and an underlying assumption that once you sink a ground it's good forever. It isn't.
I'm truly surprised that they don't have intensive real time monitoring with sensors through their whole system.
Proper engineering and maintenance of such a critical system demands it.
It all started 2 years ago when a student majoring in EE took an exotic canoe trip on the Amazon. One day the canoe capsized while he was studying and his book sank to the bottom. Thee eels read voraciously and learned about series parallel wiring of batteries. An idea was born.
And so now we have Electric Eels on a Train!
Transients caused by the inherent imperfect third rail to car contacts causes a ringing (oscillation) in the system ...
Oh, sure - blame the homeless.
#DeleteChrome
Unless they have recently upgraded a mass of cars or track, why does it suddenly start happening now ? The system has been in use and fairly reliable for a long time. I have no proof, but the suspicious borderline paranoid inside me is screaming that someone is hacking at the electrical infrastructure that feeds the Bart system, and the problem lies outside their direct observation, and is likely with PG&E's supply system to Bart. PG&E has demonstrated the disregard for maintenance, monitoring, and the security incompetence in the last few years to allow for something like this. It will likely take some outside support for Bart to prove the failures don't lie inside their infrastructure to get PG&E to even begin to look at their own systems.
errr....umm...*whooosh* *whoosh* Is this thing on ?
...when all their money is going to high salaries and benefits for union employees?
Over 200 BART employees earned over $200,000 a year in total compensation...
Those look mostly like executives, which are definitely NOT Union positions. The Unions are the ones trying to get some of that executive salary down to the real workers.
The only thing worse than a Democrat is a Republican.
I had a boss once who hired a consultant and was angry when the consultant told him to do the obvious thing.
"You know what a consultant is?" he groused. "Someone who borrows your watch to tell you the time."
I thought about this for a moment. "Yeah, but what's he supposed to do if you're standing there with the watch on your wrist and you don't know what time it is?"
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.