Introduction of Diesel Locomotives on the Indian Railways started in late 50’s, with the import of locomotives from M/s. ALCO, USA. With the setting up of Diesel Locomotive Works at Varanasi in the year 1961, the addition to the Diesel Locomotive fleet started at a regular pace.
In the earlier years of diesel operation, a limited demand of spares was met by Diesel Locomotive Works, Varanasi mainly through import, but the demand increased with the increasing size and age of the fleet.
It was in the context of the need for high precision components for maintenance support to the diesel fleet, that in the year 1979, a decision was taken to set up Diesel Component Works at Patiala. The Foundation Stone of Diesel Component Works (DCW), Patiala was laid on October 24, 1981 and production started in 1986. A decision was also taken that DCW will do midlife Rebuilding of Diesel Locomotives after a service life of 18 years. Accordingly, Phase-II of the project was sanctioned and the work of Rebuilding started in 1989. The name of DCW was changed to Diesel Loco Modernisation Works (DMW) in July, 2003 to signify the modernisation of Diesel Locomotives being done in the unit.