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 locomotives of Ireland
Note that narrow gauge locomotive classes included the letter N after the prefix letter, letter C was also used for Bo-Bo diesels, and that letters B, C, D, F, J, and K were used for the same wheel arrangements by the London and North Eastern Railway, while E and G changed places.