A 1953 NWF "SchiStra" (rail/road) Bus, at the Bochum-Dahlhausen Railroad Museum.
Over 50 of these were built back in the 1950s, but only 15 of those saw action on the rails, the rest was used as regular street buses. The idea behind concept was simply to make a vehicle that could be used on the roads, as well as the rails. For this purpose, the bus would stop on a tarmac-lined section of trackage, using hydraulics to lift itself, thus allowing the bogies at either end to be attached. This procedure took about ten minutes, with passengers remaining on board.
In addition to the hydraulic lifting mechanism, the bus also had two sets of brakes, regular ones for road use, and an air brake system that acted on the train wheels. Other extras included emergency brake handles in the passenger compartment, a dead man's switch in the cab, as well as the light setup required for trains, with the extra light visible near the destination indicator. Power was transmitted via the rear wheels, while the front ones didn't touch the rails.
While popular on a few routes, the concept didn't really work out, with rail service ending in 1967. The specimen you see here is the only surviving example, complete with bogies and preserved in working order.