WAP-4 is a common electric locomotive used in India. It is capable of hauling 26 coaches at a speed of 140 km/h.
The locomotive was developed, after a previous class WAP-1 was found inadequate to haul the longer, heavier express trains(24-26 coaches) that were becoming the mainstay of the Indian Railways network. It was introduced in 1994, with a similar bodyshell to the WAP-1 class, but with Hitachi traction motors developing 5000 hp (5350 hp starting).
Electricals are traditional DC loco type tap changers, driving 6 traction motors arranged in Co-Co fashion. This locomotive has proved to be highly successful, with over 800 units in service and more being produced. Newer examples have been fitted with Microprocessor Controlled diagnostics, Static Converter units (instead of arnos) and roof mounted Dynamic (Rheostatic) Brakes.
The locomotive can be seen in service across the electrified network of Indian Railways and are homed at 13 sheds (depots).