The WAG-7 is a six-axle freight locomotive of which 1,974 were built between 1990 and 2015. The designation stands for broad gauge (W), working under 25 kV AC (A), goods (G) and 7th generation. It was designed by Chittaranjan Locomotive Works (CLW) as a successor of their WAG-5 since this was not sufficient anymore with an hourly output of 3,200 kW or 4,300 hp. Now, the WAG-7 had an output of 3,990 kW or 5,350 hp. The top speed had been increased from 80 to 100 km/h, but starting tractive effort was still higher.
Although the WAG-7 is still being controlled by a tap changer, it was the winner in the trials against the thyristor-controlled WAG-8 developed by Bharat Heavy Electricals Limited (BHEL). In addition to the 1,773 locomotives built by CLW, BHEL also built 201. Some have been fitted with ballast that increases their weight from 123 to 132 tonnes, these are being called WAG-7H. Today the WaG-7 is still very important in freight service in India, although nearly 7,000 of the WAG-9 with three-phase traction motors have been built by now.
