In the early nineties, the SBB lacked diesel locomotives that could haul heavy infrastructure trains at low speeds. The seven Am 4/4 locomotives (former DB V 200s) had not proven suitable for this job and with a number of railway works planned, the need for new locomotives was also imminent. Also for the last mile cargo and shunting services, suitable diesel locomotives were needed at the time. After an international tender was issued, GEC Alsthom Transport in Valencia was selected as preferred bidder. In late 1994, the Spanish manufacturer received an order for thirty GA-DE 900 AS locomotives, which was increased to forty units in 1996.

The Am 841 / GA-DE 900 AS is based on the Spanish Class 311, which was built by state-owned manufacturers Maquinista, Ateinsa and Babcock&Wilcox for RENFE. Maquinista in Barcelona, Ateinsa in Madrid and Meinfesa in Valencia were later taken over by GEC Alsthom. The Class 311 was equipped with electrical equipment delivered by Siemens, but after the takeover by GEC Alsthom this was no longer possible.

The 920kW MTU 8V 396 TB14 diesel engine directly powers the three-phase generator. The generator then feeds the inverter, which delivers power to the four traction engines. Delivery of the locomotives started in mid-1996 and was completed mid-1997. On temporary broad gauge bogies, the locomotives were transported from the factory to the French border. From there, they were brought in batches by rail to SLM in Winterthur, where the units were prepared for their entry into service.

The Am 841 can be operated in combinations of up to three units and are equipped with train protection systems to enable mainline operations. During a reorganization of the fleets of SBB Infrastruktur and SBB Cargo, all units were transferred to SBB Infrastruktur.

Text: Theo Stolz

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