Geared steam locomotive
This gearing is part of the machinery within the locomotive and should not be confused with the pinion that propels a rack locomotive along the rack between the rails. The geared steam locomotives that have been built have been for conventional track, relying on the adhesion between wheels and rail.
Maumelle Ordnance Works Locomotive 1
Electric drive is almost universal because a railroad locomotive is a difficult environment for a mechanical gearbox, as the loads vary widely from second to second as the slack action runs in and out. Only on very small locomotives, pulling a limited number of cars, generally on level track, have there been any successful gearbox locomotive drives. In the case of Locomotive 1, the four-speed gearbox drives a jackshaft under the cab which is connected with side rods to the two driving wheels. The choice of mechanical drive may also have been driven by war availability – a generator and traction motor take hundreds of pounds of copper, which was scarce.