[www.sfexaminer.com]

"The current automatic train control system relies on wires that Muni trains have to attach to when entering subway tunnels — if a train operator doesn’t nail the precise speed needed for a train’s connector to 'catch' the overhead wire it can lead to stalled trains or damage to the overhead wires. The computers that form the backbone of that system are old and sit in often waterlogged rooms in subway stations."

This does not seem a very accurate description of an operation which presumably changes the pantographs from a high streets position to a very low level for subway overhead.