The coach in the center is a 1939 Mack. It's in my historic transit vehicle collection. The other two coaches were built by J.G. Brill. All three were originally built for the Delaware Electric Power Company. DEPCo. was forced to sell off its transit operations. It was purchased by the Delaware Coach Company. That company was sold to a public transit authority known as DART several years ago.

San Francisco Muni has an extensive fleet of trolley buses. Although the overhead wiring is expensive, they have relatively spirited acceleration and hill climbing compared to noisy roaring diesel buses, and they can maneuver around obstacles better than rail cars. The newest ones have on board auxiliary power units that allow short runs "off the wire". I remember seeing an operator trying to restore contact once as a kid when we went to the big city. The power comes from Hetch Hetchy Dam, and is therefore non-polluting.

These were electric-powered vehicles that drew their energy from overhead wires, but ran on rubber tires without steel tracks. Novice drivers sometimes took 90 degree turns too sharply, and the power poles disconnected from the wires. In such cases, he (or she?) had to diembark and reconnect the poles to the wires using a rope connected to each pole.