The cables are responsible for sending signals from the operator's cab to each of the cars in a train. It appears the cables failed on the fifth car, causing the following five cars to lock up and shut down as it was approaching the West Oakland station, according to a BART spokesman.
Engineers are still investigating the exact source of the glitch and probably won't know for a few days.
The disruption began at about 7:20 a.m. and service resumed into San Francisco at around 8:40 a.m. after the disabled BART train was cleared from tracks at the West Oakland station.