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Re: Half-a**ed-article on the errors of BART Technology
Author: mook
Date: 03-28-2016 - 09:11
> Another thing not to forget is that the tunnel(s) will reach end of life in some 40 to 60 years.
Yes, and BART has a lot of tunnels - not just downtown subways.
The Bay Tube does need maintenance, and in another 50 years will probably become a situation like the Hudson Tubes for the NEC in New York now.
The Berkeley Hills tunnel passes through the Hayward Fault. It was designed to allow for quick reconstruction of the tracks after the kind of earthquake expected at the time, but the amount of "creep" going on wasn't understood and allowed for. So some of the adjustment allowance has already been used up, which will be expensive to recover. BART crosses the Hayward Fault somewhere in Fremont too, I think on the new Warm Springs extension, but probably not in a tunnel there, or at least not in a deep one.
The line from Mission Street to Glen Park has some fairly significant hard-rock tunneling too. Though being in "Franciscan" rock there's a lot of variation in how hard it was.
Even the subways have some interesting design features. Some stations in Market St., San Francisco, for instance, are essentially concrete submarines with a bunch of concrete for ballast below the BART level that keeps them from popping up through the pavement. They're completely below sea level, which is also the water table in the lower Market area. Yes, there are pumps ...
Could any of that have been done differently? Probably, but in the 1960s when most of it was designed and built we simply didn't know about some things we do now, and didn't have some materials available that might have been helpful. Frankly, the physical structure has held up pretty well, considering that the core system is close to 50 years old (started construction on '64 or '65 iirc). Hopefully, maintenance can catch up and keep up with the changes over the next 50 years once BART runs out of new places to build to at a couple billion$ each.
Hmmm ... is the train control system really still running on Westinghouse computers? Hard to believe that might be the case - by now, the hardware at least should have been replaced by something with integrated circuits in it. ;)
Yes, and BART has a lot of tunnels - not just downtown subways.
The Bay Tube does need maintenance, and in another 50 years will probably become a situation like the Hudson Tubes for the NEC in New York now.
The Berkeley Hills tunnel passes through the Hayward Fault. It was designed to allow for quick reconstruction of the tracks after the kind of earthquake expected at the time, but the amount of "creep" going on wasn't understood and allowed for. So some of the adjustment allowance has already been used up, which will be expensive to recover. BART crosses the Hayward Fault somewhere in Fremont too, I think on the new Warm Springs extension, but probably not in a tunnel there, or at least not in a deep one.
The line from Mission Street to Glen Park has some fairly significant hard-rock tunneling too. Though being in "Franciscan" rock there's a lot of variation in how hard it was.
Even the subways have some interesting design features. Some stations in Market St., San Francisco, for instance, are essentially concrete submarines with a bunch of concrete for ballast below the BART level that keeps them from popping up through the pavement. They're completely below sea level, which is also the water table in the lower Market area. Yes, there are pumps ...
Could any of that have been done differently? Probably, but in the 1960s when most of it was designed and built we simply didn't know about some things we do now, and didn't have some materials available that might have been helpful. Frankly, the physical structure has held up pretty well, considering that the core system is close to 50 years old (started construction on '64 or '65 iirc). Hopefully, maintenance can catch up and keep up with the changes over the next 50 years once BART runs out of new places to build to at a couple billion$ each.
Hmmm ... is the train control system really still running on Westinghouse computers? Hard to believe that might be the case - by now, the hardware at least should have been replaced by something with integrated circuits in it. ;)
