The reference for locomotives and railcars
Bern-Lötschberg-Simplon Railway Ce 4/6 and Ce 4/4
Switzerland | 1920 | 17 produced
Works photo of the SLM
Works photo of the SLM
SBB Historic

At the time of the First World War, the government of the Canton of Bern decided that the branch lines of the BLS Group should be electrified and operated with the abundant water power available in order to do something about the acute shortage of coal. An electric locomotive had to be developed for these railways, which would achieve a low axle load and could replace the existing steam locomotives in all train types. This meant exactly that at 1.5 percent 310 tonnes should be pulled at 35 km/h, as well as 180 tonnes at 2.5 percent at the same speed. In addition, these speeds should not only be maintained, but it should also be possible to accelerate these weights from a standing start to the specified 35 km/h within four minutes.

To speed up development, a scaled-down version of the Be 4/6 introduced at the SBB at the same time was created. 14 units were initially built in 1920 and three more in 1924, which were slightly more powerful and 10 km/h faster. They were spread among the BLS subsidiaries and, if necessary, exchanged with one another. Since they were created by order of the government, they quickly earned the nickname “decree mills”.

In their original design, the locomotives had two bogies, each with two coupled axles and one carrying axle. The buffers and couplings, as well as small hoods were attached to the bogies. This meant that the locomotives could actually be assigned to the design of the crocodiles, which, however, was rarely actually stated due to the very small front end. The power came from a traction motor that stood on the bogies and drove a jackshaft.

Schematic drawing with dimensions
Schematic drawing with dimensions
Locomotive Magazine, May 1921

Between 1954 and 1956, the carrying axles and front hoods were removed from the ten most recently built locomotives, since the branch lines could now cope with the higher axle loads. They could now come up with a higher adhesion mass and were given the designation Ce 4/4. The engines that were not converted were retired by 1973 at the latest, the converted ones between 1975 and 1988. Two units with only one traction motor were in service for a long time as shunting locomotives in the Böningen workshop. A Ce 4/6 and a Ce 4/4 are still preserved today.

VariantCe 4/6Rebuilt Ce 4/4
Built1920, 19241954-1956
Manufacturermechanical part: SLM, electrical part: Oerlikon, BBC
Axle config1-B+B-1 B-B 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length47 ft 2 9/16 in40 ft 5 13/16 in
Wheelbase34 ft 7 3/8 in25 ft 1 3/16 in
Fixed wheelbase9 ft 6 3/16 in
Service weight154,323 lbs141,096 lbs
Adhesive weight132,277 lbs141,096 lbs
Axle load33,069 lbs35,274 lbs
Power sourceelectric - AC
Electric system15.000 V 16⅔ Hz
Hourly power987 hp (736 kW)
Top speed40 mph47 mph
Power Plant
Calculated Values
electric locomotive
last changed: 03/2022

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