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). The WDS-3 is used mostly in the Northern Railway Zone (NR). All these locomotives were withdrawn and scrapped by the late 1990s.
The history of WDS-3 class starts in the early 1960s with the aim of the Indian Railways to address the growing requirement for a new shunting locomotive class. These locomotives were designed by Maschinenbau Kiel (MaK) to the specifications set by the Research Design and Standards Organisation (RDSO).[2] Many aspects of this locomotive were taken from the DB Class V 60.
They use Suri hydrodynamic transmission developed for these diesel locomotives and were designed as shunting-cum-shuttle service locomotives.[2] For this purpose, the reversing gear box attached to the Suri transmission was designed to have two gear stages; in the lower gear, designated as "shunting gear", the locomotive was designated to have a maximum speed of 27 km/h and in the higher speed gear designated as "mainline gear", the maximum locomotive speed was 65 km/h.[3] The locomotive was fit for both shunting and mainline type of services up to a limited speed of 65 km/h.[3] Subsequently, it was decided to manufacture locomotives of similar type ingeniously by Chittaranjan Locomotive Works (CLW). These locomotives are designated as WDS-4 class.
When the lot of 7 WDS3 shunters came, initially they had a lot of troubles with these locomotives, but the trouble was confined more to the power pack than to the transmission.[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. These units were reclassified as WDS-4Cs. By 1990s all units were withdrawn from service and were scrapped.[4]
