BART officials say a major service interruption Monday morning in the Transbay Tube was likely triggered by circuit breakers inexplicably tripping inside the underwater tunnel. They also say the issue took crews more than an hour to resolve.
That issue halted service on the red line and portions of the green line for several hours Monday morning.
According to spokesman Chris Filippi, the latest mishap – exactly a week after a similar but apparently unrelated issue last Monday morning – came after “multi-purpose” relay switches tripped at about 5 a.m. The switch activation led the system’s third rail to lose power on a section of track leading from the East Bay into San Francisco.
The circuit breaker issue forced BART to single-track San Francisco-bound trains from West Oakland until after 6:08 a.m., when crews were able to reset the switches, Filippi said.
Dispatch recordings of Monday’s incident show that after two technicians were granted permission to go into the tunnel to deal with the incident, the work did not go smoothly.
“Power 43, the breaker failed to close,” a controller said during the incident, but a reset several minutes later eventually did “close” the circuit. Power was restored at 6:08 a.m., but it took some time before full service was restored.
Meanwhile, a separate incident in the Transbay Tube a week ago is still under investigation. The dispatch recording shows the operator of that train reporting an explosion in the tunnel. The operator attributed the explosion to possible insulator failure while talking to BART dispatchers.
Five days before that, an insulator failure outside of the tube triggered morning and midday delays around the Glen Park station.
The latest in-tunnel incidents come as BART has ordered a root cause analysis of an Aug. 29 incident in which a train operator was forced to stop after smoke from a blown insulator blocked her view of the tunnel.
BART officials have not been able to determine a precise cause for that incident or what caused an Oct. 7 incident near the Embarcadero station. BART officials say unspecified debris in the tunnel may explain that incident.
Source: NBC Bay Area
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