Seattle has this system all over downtown. Buses have two poles that go up to wires above the street, to power electric motors. Sometimes, the poles demagnetize

Seattle has this system all over downtown. Buses have two poles that go up to wires above the street, to power electric motors. Sometimes, the poles demagnetize and fall off the wires, so the driver has to go behind the bus and clap them together, and guide them back up to the wires.