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.
Track gauge conversion
Few steam locomotives are constructed to allow for gauge change. Those that are include some in East African Railways, Garratts, and the Victorian Railways R class R766. Construction of steam locomotives in this way is difficult due to the position of the boilers and the fireboxes. The gauge change is only to a wider gauge.