rail10 wrote:In a event of a computer failure on Bart and la subway controlling them will they stop?In general, yes, the systems are designed so that failure of the critical computer systems causes trains to stop. The trains (they have drivers, you know) can then proceed at low speed after contacting the dispatcher. This is pretty much standard.
Of course you can never make a system completely failsafe against all possible failure modes, but for the most part they fail safe under almost all conditions There was an infamous bug in the design of the systems used for BART and Washington Metro which could cause trains to accelerate and crash.... but BART fixed the problem back in the 1980s, before there were any crashes. WMATA in Washington didn't, and the result was the crash last year.