Geared steam locomotive
A geared steam locomotive is a type of steam locomotive which uses gearing, usually reduction gearing, in the drivetrain, as opposed to the common directly driven design.
Steam motor
All steam motors had the following characteristics:
Motors were of a standard size, according to the manufacturer's product line. Where greater power was required, multiple motors were used, one per axle or bogie.
The crankshaft and often the valve gear, was enclosed within a crankcase that contained an oil sump. This provided a generous supply of lubrication and also excluded dirt.
This allows a high crankshaft speed, encouraging efficiency. Although not all geared steam locomotives made use of this, particularly the US designs such as the Shay and the Climax, it was an essential part of the steam motor concept.