Alstom Prima H4

The Prima H4 is a dual-power shunter that won a tender by SBB in 2015 to replace old four- and six-axle diesel and electric shunters. Although it was developed in Belfort, France, it has much in common with the H3 from Alstom's works in Stendal, Germany. Its main feature is a maximum output of 2,000 kW under overhead line and still 900 kW on diesel power. The latter is being provided by two Caterpillar C18 with a gross output of 540 kW each. In times of low power demand, only one engine is running. 47 of this basic bi-mode variant have been built for SBB as Aem 940. In accordance with the requirements set by SBB, they have a top speed of 120 km/h for short main line runs. The service weight of 84 tonnes can be increased to 90 tonnes by means of ballast, but this reduces the top speed to 60 km/h.

The first five prototypes are not identical to the rest and were sold to Sersa in 2022. In addition to the bi-mode electric variant, Alstom offers three other variants. One is the bi-mode battery variant that replaces the twin diesel engines with a battery pack that delivers an output of up to 600 kW and only delivers 1,600 kW under overhead line. The hybrid variant combines the two diesel engines with the battery pack. A pure dual engine variant would be powered by two larger 900 kW diesel engines. For the time being, none of these have been ordered.