The class 001 designates six-axle diesel-electric locomotives originally fitted with 1,200hp Crossley two-stroke diesels. They were intended for passenger and freight service and were built by Metropolitan-Vickers in Manchester. The low reliability of the Crossley engines meant that from 1968 they were rebuilt to engines of the EMD 645 type. These also worked on the two-stroke principle and initially produced 1,650 hp. Since the propulsion electronics and the cooling system were stressed with this power, the power was soon reduced to 1,325 hp. The 60 locomotives provided valuable services until they were replaced by new class 201s in 1994. 