Traction

As of March 2007, 17,810 kilometres (11,067 mi) of the total 63,465 km (39,435 mi) route length is electrified. Most places use 25,000 V AC through overhead catenary delivery. A major exception is the entire Mumbai section, which uses 1,500 V DC. This is currently undergoing change to the 25,000 V system, and is scheduled for completion by 2008. Another exception is the Kolkata Metro, which uses 750 V DC delivered through a third rail.

Traction voltages are changed at two places close to Mumbai. Central Railway trains passing through Igatpuri switch from AC to DC using a neutral section that may be switched to either voltage while the locomotives are decoupled and swapped. Western Railway trains switch power on the fly, in a section between Virar (DC) and Vaitarna (AC), where the train continues with its own momentum for about 30 m through an unelectrified section of catenary called a dead zone. All electric engines and EMUs operating in this section are the necessary AC/DC dual system type (classified "WCAM" by Indian Railways).