 The locomotive has a 16-cylinder 710G3B diesel engine and is one of the fastest diesel-electric locomotives in service in Indian Railways.There are three variants of this loco - the original WDP-4 which is a loco, the WDP-4B which is a weighted loco with a single cab and the newest WDP-4D which is a loco with dual cabs.The WDP-4 was the loco originally designed by GM EMD and 10 of them were dispatched to India by June 2001.