Electric–steam locomotive

By the outbreak of the Second World War, 2,191 km (1,361 mi) of SBB lines (73.6% of the network) had been electrified, whilst the price of imported German coal kept rising.

In an attempt to save on coal the Swiss Federal Railways fitted two small 0-6-0 steam shunters of the class E 3/3 with a pantograph.

The firebox was retained, usually keeping hot embers, with a classic fire for longer operation on non-electrified tracks.

The water circulation pump, the control circuit and the lighting were powered by a battery that was charged from a rectifier fed by one of the transformers.

[4] This allows keeping the well insulated boiler warm overnight or even to start heating automatically in the early morning.