Indian locomotive class WAP-7


The Indian locomotive class WAP-7 is a class of 25 kV AC electric locomotives that was developed in 1999 by Chittaranjan Locomotive Works for Indian Railways. Its class designation denotes a broad gauge (W) alternating current passenger locomotive of the 7th generation. They entered service in 2000. A total of 2081 WAP-7 locomotives have been built, with more units being built at CLW, Banaras Locomotive Works and Patiala Locomotive Works.
The WAP-7 has been serving passengers for Indian Railways since their introduction in 1999. It is a passenger variant of the WAG-9 freight locomotive with a modified gear ratio to pull lighter loads at higher speeds. With an output of 6,125 hp, it is the most powerful passenger locomotive in the Indian Railways fleet, and the most numerous passenger locomotive in India. The WAP-7 is capable of hauling 24 coach trains at speeds of 130 km/h.

History

The WAP-7 is largely used by most regional zones of Indian Railways. As of October 2021, all of these are fitted with H-type transition couplers which are compatible with both screw coupling and centre-buffer coupling. In February 2017, Banaras Locomotive Works built their first WAP 7 class locomotive.
In 2019, a variant of the WAP-7, designated the WAP-7HS, was introduced for higher speeds. The WAP-7HS has a max speed of, and is capable of hauling a 24-car train at as opposed to the of the original. Indian Railways plans to use the WAP-7HS for Shatabdi, Rajdhani, and Duronto express trains. However, as of September 2022, it has not been confirmed if any others have been built, and the single completed WAP-7HS has remained restricted to operation.
In 2025, a variant of the WAP-7, designated the WAP-7AD, was introduced with an aerodynamic design. The WAP-7AD has a maximum speed of, and is capable of hauling a 24-car train at, as opposed to the of the original. Indian Railways plans to use the WAP-7AD for Amrit Bharat Express & other Express trains. The first WAP-7AD 37873 entered service on September, 2025 hauling 12284 Ernakulam Duronto express. A pair of WAP-7AD, painted with Amrit Bharat livery are currently parked at ICF, Chennai waiting for rake and route allotment.

Head-on Generation (HOG)

Many locomotives of this class are fitted with head-on generation, eliminating the need to have separate End on Generation sets or DG sets for supplying power to the train and thus resulting in significant savings on maintenance and running costs. The HOG transfers electric power from the loco's pantograph to the coaches instead of EOG where a power car equipped with diesel generator capable of generating adequate power of 3-phase 50 Hz 415 V / 750 V AC is provided at either end of the train rake to supply power.