Wikipedia
Kleinlokomotive
A Kleinlokomotive or Kleinlok (literally: "small locomotive"; plural:Kleinlokomotiven) is a German locomotive of small size and low power for light shunting duties at railway stations and on industrial railways. It is usually powered by a diesel engine. However Kleinloks with steam, petrol or electric engines were also produced.
After testing several trials locomotives, the Deutsche Reichsbahn (DRG) placed various types of such locomotives into service from 1930 onwards. Industrial lines and railway workshops generally procured the engines of the same design.
In Switzerland Kleinlokomotiven were used as light rail motor tractors.