In the early 1960s Indian Railways needed a reliable diesel workhorse to gradually replace its steam locomotive fleet. Equal numbers (40 each) of ALCO's DL560C and EMD's SD24 were chosen for trials. More locomotives of each of these were purchased for more trials. Indian Railways was keen on producing these locomotives in the country rather than depending on imports. EMD did not agree for a Transfer-of-Technology, while ALCO did. Thus ALCO DL560C was chosen for the job due to its easy maintenance, reliability and simple operation.
The locomotive was classified as WDM-2 series and was assigned to haul long/short distance passenger trains and freight. These units are still in service. When the production of WDM2 ceased, there were 2706 locomotives in the system. The production began in the late 1960s, and went on till the late 1990s.
After importing a couple of batches of this locomotive, Indian Railways started manufacturing them in India itself and also introduced modified variants of the same locomotive. Some were fitted with a less-powerful engine, classified as WDS series, and were meant for shunting duties in marshalling yards across the country. Various variants, all based on the ALCO DL560C power-pack were developed. The original powerpack churned out 2600hp worth of power, while after modifications, Engineers at DLW managed to extract as high as 3300 hp of power. The newest variant based on the DL560C power pack is the WDM3D, which is complete with micro-processor controls, better ergonomics, etc.