First indigenous WAM 4 class locomotive was manufactured by Chittaranjan Locomotive Works around 1970–71 and manufactured until 1997. They are mixed type of locomotive and can be used for both passenger and freight operations. This is the most successful electric locomotive class used in Indian Railways

Indian Railways

Indian Railways , abbreviated as IR , is a departmental undertaking of Government of India, which owns and operates most of India's rail transport. It is overseen by the Ministry of Railways of the Government of India....

. Some of its variants are WAM 4 6P, WAM 4P and WAM 4B. A single WAM 4 loco is capable of hauling 24 passenger coaches. It is so successful that Indian Railways used its basic design for manufacturing various other locomotives,such as, WCAM 1

WCAM 1

WCAM-1 is a class of locomotives used in the Indian Railways system. They are the first of the WCAM series. These locos can be seen in Mumbai-Vadodara-Ahmedabad section but occasionally they travel up to Pune or Indore but not beyond these because the maintenance facilities are not available...

, WAG 5A, WCG 2, WAG 7.