Indian locomotive class WAP-7
Indian Railway passenger class electric locomotive
The Indian locomotive class WAP-7 is a class of 25 kV AC electric locomotives that was developed in 1999 by Chittaranjan Locomotive Works (CLW) for Indian Railways. Its class designation denotes a broad gauge (W) alternating current (A) passenger (P) locomotive of the 7th generation (7). They entered service in 2000. WAP-7 locomotives are being built at CLW, Banaras Locomotive Works (BLW) and Patiala Locomotive Works (PLW).
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.
01History
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 180 km/h (110 mph), and is capable of hauling a 24-car train at 160 km/h (99 mph) as opposed to the 140 km/h (87 mph) 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 130 km/h (81 mph) 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 180 km/h (110 mph), and is capable of hauling a 24-car train at 160 km/h (99 mph), as opposed to the 140 km/h (87 mph) of the original. Indian Railways plans to use the WAP-7AD for Amrit Bharat Express and other Express trains. The first WAP-7AD 37873 entered service in 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.
02Head-on Generation (HOG)
Many locomotives of this class are fitted with head-on generation (HOG), eliminating the need for separate End-on Generation (EOG) sets or DG (Diesel Generator) sets to supply power to the train, thereby resulting in significant savings in maintenance and operating costs. HOG transfers electric power from the locomotive's pantograph to the coaches, unlike EOG, in which a power car equipped with a diesel generator capable of generating sufficient three-phase 50 Hz 415 V / 750 V AC (called 'head-end power') is provided at either end of the train rake to supply power.
03Locomotive sheds
Sources and credits
This article is adapted from the Wikipedia article “Indian locomotive class WAP-7”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- BZA WAP7.jpg by Raju2789, CC0
- Indian Electric Locomotive WAP-7 ED - 39231.jpg by Sameer2905, CC BY-SA 4.0
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