Shutting down part of the system
BART has had two major unplanned service stoppages in the past few weeks, both caused by fires. The first one was between Pleasant Hill and Walnut Creek, and the second near Fruitvale. In each case, in addition to stopping service at/between the affected stations, they also stopped service to adjacent stations (no service between Lafayette and Concord, or Lake Merritt and San Leandro). My question is simple: Why?
I want to be clear: I'm not bashing BART here. I assume they had a good reason to stop service where they did, I just don't know what it is. In the Pleasant Hill incident, it looks like there are sufficient crossovers to turn the Pittsburgh / Bay Point trains around at Walnut Creek, and the SFO trains at Pleasant Hill. I didn't look as closely at the track configuration on the Fremont line, but I'd be surprised if the lack of crossovers was the only reason they set the size of the shutdown how they did. What other factors come into play here? Can the third rail power not be shut off in small enough segments? Is there something about the crossovers that I'm missing? Passenger capacity issues? (I call bullshit on that one for the Pleasant Hill incident; Lafayette was in total gridlock)