Garrandale has been awarded a £15m contract by Bombardier to help deliver the Crossrail train contract.
The deal will see Garrandale supply the front ends of the 65 Crossrail trains, as well as all the assembly and production line equipment that Bombardier will use to build the rest of the trains.
The company will also provide specialist train-washing equipment for the new train maintenance depot being built at Old Oak Common.
Garrandale chief executive Malcolm Prentice said: "From the time the aluminium raw material reaches the factory at Derby until the trains actually go into service and are washed at the maintenance depot in west London, Garrandale will be part of every process. This win against fierce global competition is a tribute to the skills and record of the Garrandale team."
Peter Doolin, vice-president for project management and head of Crossrail at Bombardier Transportation, said: "Garrandale has proven once again that Derby and Derbyshire have the world-class skills and the determination to deliver a flourishing rail sector far into the future. We congratulate Mr Prentice and the Garrandale team on succeeding through our tough procurement process."
Bombardier won the £1bn contract to supply 65 new trains for Crossrail in February 2014.
The new rolling stock will be designated Class 345 and will be 200m long with nine carriages, and be able to carry up to 1,500 passengers. Features include air conditioning and inter-connecting walk-through carriages, as well as on-train passenger information systems. Bombardier will also emphasise energy efficiency with on-train energy management systems.