The Indian locomotive class WAP-4 is a class of 25 kV AC electric locomotives that was developed in 1993 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), AC Current (A), Passenger traffic (P) engine, 4th generation (4). They entered service in late 1994. A total of 778 WAP-4 were built at CLW between 1993 and 2015, which made them the most numerous class of mainline electric passenger locomotive until the WAP-7.