The class WDS-3 was a diesel-hydraulic locomotive used by Indian Railways for shunting and doing departmental work.
The model name stands for broad gauge (W), diesel (D), shunting (S) 3rd generation (3).
[3] The locomotive was fit for both shunting and mainline type of services up to a limited speed of 65 km/h.
[citation needed] But in course of time, going into detail about the troubles that were being experienced and the mechanics were able to get over a lot of these difficulties and in-fact the transmission was also modified to suit with the engine.
[citation needed] Between 1976 and 1978 all seven units were rebuilt to WDS-4B specifications by CLW, and received a new engine and a simplified transmission.