SBB Brünig

Multipurpose locomotive HGe 4/4 II for operation on adhesionand cog wheel lines

The FO reckoned with a strong traffic increase because the opening of the Furka tunnel was imminent (opened in 1982). High growth rates were expected at that time especially with locomotive-drawn trains in transit traffic. The six HGe 4/4 I locomotives built in the forties proved however inadequate for these trains due to their low maximum speed and their susceptibility to breakdowns. Therefore a decision was made to procure a new series of locomotives together with the SBB.
At the beginning of 1983, the manufacture of a preliminary series of five units was given in commission. Three units (101-103) were for the FO, two for the SBB (1951-1952). It was also agreed at the same time that, with the delivery of the eight SBB series locomotives in 1985/86, the two SBB-prototypes would be handed over to the FO after corresponding adaptations.

The locomotive body was manufactured in lightweight steel construction and weighed alone only 5.8 tons! In order to minimize stresses resulting from the rack-and-pinion and the traction wheels, a novel differential drive developed by SLM was used. All four axles are each driven by a pulsating-current traction motor. These are fed by two two-quadrant power converters of the oil-bath type.
The locomotives have regenerative brakes independent of the overhead contact wire, whose switching has been adopted by the local transit shuttle trains. The traction control electronics base on ABB’s microprocessor controlled MICAS-S system and consists of two identical units.

Since the vehicles' performance prooved satisfactory the FO ordered an additional number of three units. In addition to that the BVZ received five identical locomotives in 1990 so that a total number of 21 cog wheel locomotives of type HGe 4/4 II are in service in Switzerland.