These locomotives originated in a narrow gauge design used on WWI trench railways. After the war the design was developed for industrial use including as standard gauge versions.
Just remembered the ever entertaining "Curator with a Camera" series from the British National Railway museum featured an industrial version of one of these locos.
Thank you for the information. The small "traktor" has an interesting history. Their small size makes them very suitable for use in warehouses and engine shops where they can shunt wagons and locomotives around as needed.