What’s Frying the Electrical Systems on BART Trains? - Page 1
Forum section: electronics / general

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 18, 2016, 02:58:27 am
content: Pinched link from Slashdot, but I thought it was of interest.Not sure why it would be so hard to solve, but obviously all the relevant information is either not published or not yet measured.http://spectrum.ieee.org/view-from-the-valley/transportation/mass-transit/whats-frying-the-electrical-systems-on-bart-trainsAny insight would be welcome.

author: ataradov
author_rank: Super Contributor
timestamp: March 18, 2016, 03:08:51 am
content: Quote from: HackedFridgeMagnet on March 18, 2016, 02:58:27 amHomeless people stealing wiring for copper. Real problem for CalTrans, a lot of traffic meter lights are out on highways because of that. BART gets affected as well from time to time.

author: coppice
author_rank: Super Contributor
timestamp: March 18, 2016, 03:21:54 am
content: Quote from: ataradov on March 18, 2016, 03:08:51 amI have worked on projects where the fibre cable had to be printed along its entire length with something like "Optical fibre cable - contains no copper" because of this problem.

author: ataradov
author_rank: Super Contributor
timestamp: March 18, 2016, 05:18:23 am
content: Quote from: wilfred on March 18, 2016, 05:16:44 amStealing would make them thieves, yes. Most of the time they are homeless as well.

author: station240
author_rank: Unknown
timestamp: March 18, 2016, 05:30:34 am
content: My guess would be a some bad (or cut) return cables to 0V.When you cross from a good section to bad, the wheels bridge the gap.Real pain to find apparently as simple test gear as there are multiple points the cable connects to the rails, maybe 4 wire resistance works.Could also be a shorted diode in a bridge rectifier, or fault that results in the same. You'd get double the voltage when the AC is present on the DC rail (well 50% cycle).If it's intermittent (short only occurs at max current/voltage) then it would be hard to trace.

author: iampoor
author_rank: Frequent Contributor
timestamp: March 18, 2016, 08:11:22 am
content: Steeling copper from air conditioners is also a huge problem in California. Flat roofs and air conditioners everywhere is not a very safe combination.

author: ajb
author_rank: Super Contributor
timestamp: March 18, 2016, 12:11:23 pm
content: On a related note, Washington, DC's metro rail system, which is slightly longer than BART but with twice as many stations and twice as many riders, was completely shut down this past Wednesday for emergency inspection of electrical connections. Apparently there was a tunnel fire the day before of a similar nature to one a year ago that killed one person when a tunnel filled with smoke.Both systems seem to be hamstrung by similar problems, in particular the lack of maintenance windows and no redundancy in rail lines. Three hours is barely enough time to get a crew to a site and get the tools unpacked before you have to pack everything back up and get out of the way for the morning rush, let alone get any work done in between. If you want to get a real project done you have to shut down track during operating hours, and if you've only got two tracks on all of your lines, you're stuck single-tracking around the work area which destroys your throughput.At least in DC, no one wants to reduce operating hours (which is understandable) to increase the nightly maintenance window, but then people get frustrated when things keep breaking down, and they have to put up with single-tracking on the weekends. The only way to avoid both of those problems is to add a third track to all of your lines so that you can always work on one track while maintaining two-way traffic on the other two, but that's a colossal expense, and even if you can commit the capital you still have the problem of when you can do the work to build it!Speaking of capital, local politics is the other big problem for any transit system. DC's metro system spans two counties in Virginia, two counties in Maryland, DC itself, and the federal government. Only a small geographic portion of MD and VA are within metro's service area, so the states themselves aren't a huge help, so getting everyone on board with any sort of big project is going to be like herding cats. It takes a lot of money to build a solid transit system and it's too easy to slip up and wind up in a death spiral of declining service->declining ridership->declining revenue->declining service... and getting six different jurisdictions to commit to 5+ year development plans is virtually impossible. So systems keep limping along, because everyone relies on them but no one is willing to support them properly.In the end, the usual solution is to chicken out and go for something easier and cheaper and with near-instant gratification by comparison--start looking at lists of proposed development plans for different rail systems--the vast majority end with "but they decided to build highways instead".

author: German_EE
author_rank: Super Contributor
timestamp: March 18, 2016, 04:35:51 pm
content: I don't think this was cut cables, ground or otherwise, mainly because the BART electricians don't know what's causing the spikes and they would have noticed copper cable going missing. Some possible guesses:1) One or more ground connections that are now not properly grounded at the far end, this then arcs over when a train passes by causing a surge.2) A design fault in the DC motor subsystem.3) Pilot error, the engineers driving the trains are doing something that is OK on an AC motor train but can cause problems on a DC motor train. A car analogy, you can start a benzine automobile instantly but when starting a diesel car you need to wait for the glowplugs.4) A problem with the electrical power feeding the tracks. The BART electricians will only check their network and the PG&E linemen will only check their side, the two need to talk.5) Sabotage.6) Poor timing, is this something to do with two or more trains on the same length of track at the same time and some funky power surges being created as the two vehicles interact. I once saw an elevator system with a relay logic bug where if two elevator cars both opened their doors at exactly the same time the breaker powering the lights would trip. That one took a while to find.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 19, 2016, 03:27:39 am
content: QuoteThe newer cars are 30 years old.I guess whatever electronics in the cars in near its use by date.It also seems that the cars all seem to die in large batches, larger than one train anyway which seems strange.Probably it is just a case of not been given the facts from the newspaper.

author: SeanB
author_rank: Super Contributor
timestamp: March 19, 2016, 05:39:51 am
content: So, probably the large DC rail capacitors in the thyristor power supply are well past the replace by date, along with all the small electrolytics on the control boards. That can be the cause for batch failures, as the boards were probably made with caps from the same batch, and likely were made as a few hundred each time.

author: German_EE
author_rank: Super Contributor
timestamp: March 19, 2016, 09:30:12 am
content: Agreed. After thirty years of heavy use those trains are coming out the other side of the bathtub curve.

author: Jeroen3
author_rank: Super Contributor
timestamp: March 19, 2016, 10:57:05 am
content: Quote from: German_EE on March 19, 2016, 09:30:12 amCorrect, and inflexible management and regulations prohibit replacing parts for newer more reliable alternatives. Instead, al the old crap is revived and put to use again for a few months, before failing again.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 19, 2016, 03:40:14 pm
content: Quote from: blueskull on March 18, 2016, 05:21:38 amThe states in the US that I have been in all apply the stickers on the inside of the windshield. So thieves and the whether usually can't affect them. They also use stickers are made of a material that shreds if you try to take it off.FWIW I lived in Virginia when they build the Washington DC metro. They taxed the hell out of motorists all over the state to pay for a system that only benefitted those living in the immediate DC area. The rest of the state got NOTHING. I expect they would have a very hard time trying to convince the taxpayers state wide to do spend MORE money to replace or upgrade the system.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 19, 2016, 03:54:59 pm
content: Quote from: iampoor on March 18, 2016, 08:11:22 amStealing outside AC units is a HUGE problem in my area. A friend of mine designed a steel cage to go over the outside units to prevent theft and he is now making afortunebuilding and installing them.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: March 19, 2016, 09:18:31 pm
content: Quote from: Stray Electron on March 19, 2016, 03:54:59 pmHopefully with high voltage on the cage. Doing Momma's work, one bzzz bzzz bzzz at a time

author: SeanB
author_rank: Super Contributor
timestamp: March 20, 2016, 11:40:27 am
content: Here there are no houses with brass or metal house lettering outside, all been stolen. There was even a thief who stole a stainless steel statue from right outside the city hall, in sight of the guards. Then there were the thieves who vandalised a national monument for the massive bronze panels these. Then the elephant saga........

author: G7PSK
author_rank: Super Contributor
timestamp: March 20, 2016, 03:09:48 pm
content: What about a problem with the regenerative braking systems, perhaps on a following train raising the voltage on the line.

author: tooki
author_rank: Super Contributor
timestamp: March 20, 2016, 07:49:30 pm
content: Quote from: SeanB on March 20, 2016, 11:40:27 amThat reminds me of when I was living in the Baltimore area. There was a string of thefts of public lamp posts. And we're not talking little ones — these were 10 meters tall, and when I say a string of thefts, I mean thatover 130 of themwere stolen over just a few weeks!!!http://www.nytimes.com/2005/11/25/us/light-poles-are-vanishing-and-baltimores-police-are-baffled.html?_r=0

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 20, 2016, 08:15:48 pm
content: Maybe some big-ass MOVs would help, at least as an interim fix.

author: rrinker
author_rank: Super Contributor
timestamp: March 20, 2016, 11:01:47 pm
content: More on the sad state of the quality of work done, if 30 year old electric railcars are past their prime. Stuff built at the turn of the 20th century was still in regular use right into the 70's and even 80's in some cases. They roll out this newer stuff and in some cases it's broken before it even gets into general service.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 21, 2016, 05:48:07 am
content: Quote from: rrinker on March 20, 2016, 11:01:47 pmWe had the same in Sydney, fond memories of my youth, riding the red rattlers.But I dont think we can expect the same sort of longevity out of 1980s power electronics.Whatever the technology involved you would hope that the BART people, would have the ability to fix the trains fairly quickly when they do fail, and are also able to keep them maintained to a point where they do have a good MTBF.

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2016, 07:11:01 am
content: Quote from: HackedFridgeMagnet on March 21, 2016, 05:48:07 amThat would require them to actually have those high salary skilled staff around, and train apprentices to do the work and eventually take over. Not going to happen as the bean counters see the staff as something you get the cheapest person, and regard them as all interchangeable. Turns out skill is not something you can get from reading a comic book.......

author: Towger
author_rank: Super Contributor
timestamp: March 21, 2016, 07:44:46 am
content: If they are like here, they have very few, if any qualified staff left.I got a tour of our main train depot back in the late 80s. Back then they still had a full on house apprenticeship training program. But could not get qualified engineers to join, or in their words new engineers leave collage and do not want to get their hands dirty.At that time they were trying to document the remaining engineers knowage in an expert system.Roll on a couple of decades and the apprenticeship training is long gone. Their current mode of operation appears to be to replace the rolling stock every few years. I have heard they have both scrapped and have in storage a large number of trains which should have many more years if life in them, but have niggling technical problem they can't fix. Or more lightly can't fix in house and getting experts in is deemed non economical.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 28, 2016, 10:35:10 pm
content: https://tech.slashdot.org/story/16/03/28/0157248/why-bart-is-falling-aparthttp://www.nbcbayarea.com/news/local/BART-Needs-100-Thyristors-Power-Surge-Concord-Bay-Point-372550951.htmlsome further updates.It does sound like they need to throw the whole thing away. 5' 6" gauge. WTFIt does seem like a wad of MOVs could help.

author: rrinker
author_rank: Super Contributor
timestamp: March 30, 2016, 02:32:36 am
content: Why's the wide gauge a facepalm? It's a private system that has no reason to interchange with the rest of the nationwide rail network. Wider wheelbase can make is more stable and have a higher capacity per train length and car. The real facepalm is this idiotic high speed rail idea in California that will cost billions of dollars for 100 miles of track and won't be all that "high speed". Or other proposals for "high speed" of 100mph - STEAM TRAINS did 100 MPH 100 years ago. I'm all for trains, but they put up these boondoggle ideas that go where no one really needs them (which will cause them to be endless money pits as there aren't enough riders..) but then they do everything they can to make sure we don't get them were people would and could make use of them.I take the train whenever I can - I hate the circus that flying has become these days with extra charges for everything and the silly "boarding group" stuff that put people all over the plane at random, so you end up crawling over people who are already seated, plus the cattle car cramped conditions. Even an economy seat on a train has room to stretch out in. Plus trains are much more efficient than cars, buses, trucks, or planes.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 30, 2016, 08:27:22 am
content: Many years ago in our country we had three states that decided on different railway gauges. AFAIK we are still stuck with 2 different gauges. Which makes interconnection problematic.As you say 5'6" may be better, though I dont know if it is, but buying standard gauge trains must be cheaper than making or buying them to your own gauge.

author: ataradov
author_rank: Super Contributor
timestamp: March 30, 2016, 08:30:43 am
content: Quote from: HackedFridgeMagnet on March 30, 2016, 08:27:22 amThat's why BART did not buy any in the last 30 years

author: tooki
author_rank: Super Contributor
timestamp: March 30, 2016, 10:53:13 am
content: Quote from: HackedFridgeMagnet on March 28, 2016, 10:35:10 pmUgh, that article makes me so mad!! "Thyristor" is "difficult to pronounce"? Really? "THIGH-rih-ster"?!? (Never mind that that should be "thigh-RIS-ter".) I'm American and it makes me fume that so many Americans, including the media, not only condone but encourage ignorance. Talk about dumbing things down…</rant>

author: SeanB
author_rank: Super Contributor
timestamp: March 30, 2016, 07:14:15 pm
content: I would guess the "spike" came from stolen cables on the track section, and that they are not admitting this as it would show up just how poor the security is. That they are paying $100k for 1000 thyristors points to them being an obsolete puck style device, and while there likely are a few better more modern replacements the hide bound approval process to get a part with a different part number approved is what is holding them back. The thing is that there likely are modern devices available ( most likely a part that is already used as a replacement in fork lift and other DC motor drive applications dating from the year Tut when this was designed) which either is a direct fit, or which might only need a snubber or a few resistor values changed in the drive, or which just needs a different heatsink arrangement to fit the 4 bolt mounting and the flexible lead tails they have.

author: vodka
author_rank: Frequent Contributor
timestamp: March 30, 2016, 08:23:30 pm
content: I don't know how many copper steal in other countries but in my region is demented, suming the 4 provinces reach 70,000 meters the stolen copper from the railroad.Besides there are that to sum the stolen copper at Rural houses and exploitation agricultural. Now we have a police with a cost about 2000€ with a low efficent.http://www.elmundo.es/economia/2015/07/20/55abe6e7ca47415f228b4582.htmTwo stolen Rural houses and after burninghttp://www.diaridetarragona.com/reus/59634/roban-en-dos-masias-de-la-riera-de-labeurada-y-despues-las-queman

author: edavid
author_rank: Super Contributor
timestamp: March 30, 2016, 09:56:58 pm
content: Quote from: Towger on March 21, 2016, 07:44:46 amNope, that's not a problem. BART is notorious for its gold-plated benefits and retirement plan - they have no trouble retaining employees.

author: edavid
author_rank: Super Contributor
timestamp: March 30, 2016, 09:58:36 pm
content: Quote from: SeanB on March 30, 2016, 07:14:15 pmThis theory is ridiculous.

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2016, 07:01:18 pm
content: Spoornet here ( the rail carrier) invariably every day has a main line or other line delay of a few hours caused by either cable theft, overhead conductor theft or actual track theft. Hard to protect copper and brass in the open, but in a system that is mostly underground or elevated this should be doable.Spikes could also be failing power supplies, there will be large transformers and rectifiers, and a fault in insulation could be enough to kill the trtain, before a protective breaker trips out.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: April 01, 2016, 01:32:41 am
content: Quote from: HackedFridgeMagnet on March 19, 2016, 03:27:39 amThere's nothing too unusual about that. The rolling stock on the Bakerloo Line on the London Underground all dates from 1972. The Piccadilly Line uses 1973 stock and the District Line uses 1976 stock.

author: SL4P
author_rank: Super Contributor
timestamp: April 01, 2016, 02:21:16 am
content: I like the idea floated earlier about earth discrepancies between larger areas / segments of track.Effectively creating massive earth loops when the supplies are sourced from different infrastructure with different ground referencesCorrosion, even tiny resistances at 5,000A means a lot of problems!

author: johansen
author_rank: Super Contributor
timestamp: April 01, 2016, 08:46:39 am
content: Quote from: SeanB on March 30, 2016, 07:14:15 pmnot obsolete, (the specific part they want may be) but the pigtail components you mention.. those are an even older package, yet still available for some reason...

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 01, 2016, 08:55:25 am
content: Quote from: johansen on April 01, 2016, 08:46:39 amStill avaialble presumably because they're used in long-life products like trains.

author: johansen
author_rank: Super Contributor
timestamp: April 01, 2016, 09:01:17 am
content: Quote from: mikeselectricstuff on April 01, 2016, 08:55:25 amor dozens of other applications.such as HVDC electric grids. but it is quite plausible the 1000-2000 volt, 1000-2000 amp "puck" thyrister is dead. dead because the industry moved on to 5KV, 5000 amp thyristers.. and 1000 volt, 100-1000 amp IGBTs1000 volt, 100 amp pig tale thyristors are still alive.. in millions of welders around the world.

author: johansen
author_rank: Super Contributor
timestamp: April 01, 2016, 09:13:13 am
content: from Slashdot:"Indian Railways that carries 23 million passengers a day, 50 times more than BART, uses the 5' 6" gauge. It is the most popular and broadly [wikipedia.org] used gauge in the world railways. May be BART can import trucks/bogies and wheel sets from India. But India is also facing a severe manufacturing capacity crunch. It desperately needs more rolling stock and locomotives. As does Pakistan. And Pakistan's imported Chinese locomotives are plagued by maintenance issues. Pakistan is lobbying India to get some diesel locomotives. So even if BART is willing to import, it would take some doing to get India to export any."https://en.wikipedia.org/wiki/5_ft_6_in_gauge_railwayQuote from: HackedFridgeMagnet on March 30, 2016, 08:27:22 amworld would be pretty boring if everyone was the same...

author: elgonzo
author_rank: Unknown
timestamp: April 01, 2016, 09:24:48 am
content: Quote from: johansen on April 01, 2016, 09:13:13 amI chortled heartily at this bit... The world would be a much more boring place without random (Slashdot) commenters spouting funny nonsense, right?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 01, 2016, 11:13:08 am
content: Quotefrom.https://en.wikipedia.org/wiki/Standard_gaugeThose 1960s party poopers, so much fun to be had changing trains at 2 in the morning.

author: johansen
author_rank: Super Contributor
timestamp: April 01, 2016, 05:26:58 pm
content: Quote from: elgonzo on April 01, 2016, 09:24:48 amnot quite nonsense, but close.(based upon kilometers installed) at 29.3%

author: tooki
author_rank: Super Contributor
timestamp: April 01, 2016, 05:34:55 pm
content: Quote from: johansen on April 01, 2016, 09:13:13 amYeah, slashdot clearly misread wiki, as it's not "most popular and broadly used gauge in the world", but rather "the widest gauge in regular use anywhere in the world". I guess they confused broadly and broadest.

author: elgonzo
author_rank: Unknown
timestamp: April 01, 2016, 05:38:56 pm
content: Quote from: johansen on April 01, 2016, 05:26:58 pm"Most popular" does not refer to "how many kilometers" but to "how many places/countries"."Most broadly used" could be a synonym for "most popular" or it could mean "most used". But the Indian Wide Gauge is neither the most popular nor the most used gauge. So, it is quite nonsense no matter from which point of view one reads that statement. Anyway, it's not really that important...(Pointless side note: While the Standard Gauge is the most used railroad gauge in the world in terms of track kilometers, i am not quite sure whether it is the most popular. It could be that the most popular gauge is the Cape Gauge, but i am not really sure of it -- would need to compare the number of countries using Standard Gauge vs. number of countries using Cape Gauge, which could become more laborious and complicated if one would include trams/streetcars)Quote from: tooki on April 01, 2016, 05:34:55 pmYeah, it would have made more sense saying "it is the widest and the most popular broad gauge used in the world today" or something like that. Which probably was the commenters intention, but his comment is written in such a wrong way that it just became funny...(for me anyway...)

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 01, 2016, 08:45:00 pm
content: If you read the Wiki article it says that "Broad Gauge" is used on 29% of the worlds track miles. But "Broad Gauge" is a family which includes several sizes. The same article further breaks it down to say that the 5' 6" gauge is used on 11.4% of the track miles in the world. That is surely enough to make a market. I mean Apple is successful and it has bounced around near the 10% level for all of its existence.https://en.wikipedia.org/wiki/Track_gauge