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.
GE steam turbine locomotives
The turbines were designed to operate at 12,500 rpm and were paired with a generator set with a 10:1 reduction gearing. A twin-armature DC generator was used to power the traction motors, while a three-phase, 220-volt AC generator powered auxiliary functions such as traction motor blowers and providing head-end power. The latter, which provided lighting, heating, and air conditioning to passenger cars, was unusual in 1939 and would not become standard until the 1970s.