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.
Steam generator (railroad)
Steam generators were developed when diesel locomotives started to replace steam locomotives on passenger trains. In most cases, each passenger locomotive was fitted with a steam generator and a feedwater supply tank. The steam generator used some of the locomotive's diesel fuel supply for combustion. When a steam generator-equipped locomotive was not available for a run, a so-called "heating car" fitted with one or two steam generators was inserted between the last locomotive in the consist and the rest of the train.