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Why BART Is Falling Apart
HughPickens.com writes: Matthias Gafni writes in the San Jose Mercury News that the engineers who built BART, the rapid transit system serving the San Francisco Bay Area that started operation in 1972, used principles developed for the aerospace industry rather than tried-and-true rail standards. And that's the trouble. "Back when BART was created, (the designers) were absolutely determined to establish a new product, and they intended to export it around the world," says Rod Diridon. "They may have gotten a little ahead of themselves using new technology. Although it worked, it was extremely complex for the time period, and they never did export the equipment because it was so difficult for other countries to install and maintain." The Space Age innovations have made it more challenging for the transit agency to maintain the BART system from the beginning. Plus, the aging system was designed to move 100,000 people per week and now carries 430,000 a day, so the loss of even a single car gets magnified with crowded commutes, delays and bus bridges. For example, rather than stick to the standard rail track width of 4 feet, 8.5 inches, BART engineers debuted a 5-foot, 6-inch width track, a gauge that remains to this day almost exclusive to the system. Industry experts say the unique track width necessitates custom-made wheel sets, brake assemblies and track repair vehicles.
Another problem is the dearth of readily available replacement parts for BART's one-of-a-kind systems. Maintenance crews often scavenge parts from old, out-of-service cars to avoid lengthy waits for orders to come in; sometimes mechanics are forced to manufacture the equipment themselves. "Imagine a computer produced in 1972," says David Hardt. "No one is supporting that old equipment any longer, but those same microprocessors are what we have controlling our logic systems." Right now BART needs 100 thyristors at a total cost of $100,000. BART engineers said it could take 22 weeks to ship them to the San Francisco Bay Area to replace in BART's "C" cars, which make up the older cars in the fleet. Right now, the agency has none. Nick Josefowitz says it makes no sense to dwell on design decisions made a half-century ago. "I think we need to use what we have today and build off that, rather than fantasize what could have been done in the past. The BART system was state of the art when it was built, and now it's technologically obsolete and coming to the end of its useful life."
Another problem is the dearth of readily available replacement parts for BART's one-of-a-kind systems. Maintenance crews often scavenge parts from old, out-of-service cars to avoid lengthy waits for orders to come in; sometimes mechanics are forced to manufacture the equipment themselves. "Imagine a computer produced in 1972," says David Hardt. "No one is supporting that old equipment any longer, but those same microprocessors are what we have controlling our logic systems." Right now BART needs 100 thyristors at a total cost of $100,000. BART engineers said it could take 22 weeks to ship them to the San Francisco Bay Area to replace in BART's "C" cars, which make up the older cars in the fleet. Right now, the agency has none. Nick Josefowitz says it makes no sense to dwell on design decisions made a half-century ago. "I think we need to use what we have today and build off that, rather than fantasize what could have been done in the past. The BART system was state of the art when it was built, and now it's technologically obsolete and coming to the end of its useful life."
To be fair to the BART designers though, If I designed something that lasted twice a long as specced and carried four times the passenger load, I'd be pretty happy.
Actually it is closer to 30 times the passenger load, TFS lists the original spec of 100k / week , with todays usage of 430k / day ... or ~3 million / week.
To err is human; effective mayhem requires the root password!
The only thing that they really messed up was the track gauge, not using the standard gauge but a more or less unique for the BART system.
When it comes to electronics it's not impossible to replace. I don't see a $1000 price of a thyristor as something remarkable if it's a high power type.
What's more amazing is that in many cases processors designed in the 70's are still manufactured today while processor designs from the early 90's are almost unobtanium now. Just look for Z80 processors (a 70's design) at Mouser and then look for 386, 486 or 68040 processors. You can find the latter but only at more obscure vendors and sometimes they are refurbished from scrapped computers. With that as background I'd rather try to fix a computer board from '72 than one from '92 if I have the schematics. A '72 computer is either wired or hole-mounted 0.10" split DIL chips on a PCB with maybe 2 or at worst 4 layers. A '92 computer board is way tougher and requires patience since some chips aren't just surface-mount soldered but glued as well on a PCB with multiple layers.
If you want to make a system that is going to have a long lifespan, then you have to design it with a lot of standardized interfaces using connectors that are extremely common and that are easy to manufacture. And when you do that also make sure you document the interface very well, since that allows people in the future to manufacture plug-in replacement modules using modern hardware. The overall design will be more expensive but the concept lifespan will be a lot longer.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
The expected benefit was not blowing off the golden gate bridge. The BART was supposed to go to Marin. That is why the gauge is broad. It made good engineering sense based on the design requirements. Then Marin pulled out.