The EBT "doodlebug" is unique - it is the only true narrow gauge gas-electric car in the US. All others utilized some form of mechanical transmission. Interesting footnote - the engine in the EBT car was built by Brill in the 1920's originally as part of a competition for a U.S. Navy contract for blimp engines. IIRC, each competitor had to produce 6 working engines for Navy evaluation. I don't recall who got the contract, but Brill did not, and one of the engines wound up in the M-1. Through the efforts of the Rockhill Trolley Museum, the EBT, and the Friends of the EBT, the car is still servicable.