Climbing the St. Gotthard Tunnel usually required two locomotives, so the Swiss Federal Railways made several powerful double engines. It had a power output of 8800 kW, the strongest engine of its day. The couplings of the wagons could not muster this force, so the maximum power output could not be used.
In service from 1939 to 1971. A fire in one of the transformers put an end to its working life.

Verkehrshaus in Luzern, Switzerland