The Marmons were equipped with GE electrical motors and controls which had the contactors electrically advanced whereas the Twins used Westinghouse equipment with air advanced controls. According to Charlie oil leaked into the air system and messed with the Westinghouse system. Of course streetcar HL controls were also air-operated.

The Twin Coaches were based at Presidio and some Westinghouse equipped Marmons as well. The GE equipped Marmons and the really big St. Louis coaches ran out of Potrero. So I don't know if the St. Louis buses, with the most unusual S-shaped seats, had a booster button, which I thought was for hills.

You could really tell the difference in performance between the GE and the Westinghouse Marmons, but the Twins seemed the fastest, albeit Westinghouse.

I assume the new Muni trolley coaches are AC motored and IGBT's?