A common engine seen in Indian railways.It is technically known as WAP-4.

                                                 W-Broad gauge,

                                                 A-AC electric,

                                                 P-Passengers.

                   It was introduced in 1994 to haul heavier trains(24-26 coaches).It is a modified version of WAP-1.I have travelled in trains which are hauled by this locomotive.Basically an electric locomotive gets its working fuel from the overhead lines(25kv).(Warning- Don't play near these lines).Here there are around 770 locos of this type. Chittaranjan locomotive works is the company which produces electric locos for Indian Railways.

                       The loco has a streamlined twin cab carbody design with top mounted headlights.Original units weighed 120 tonnes , which was bought down to 112 tonnes through the use of lighter materials.Some of the WAP-1 and WAP-3 and all WAP-6 units were built to WAP-4 specifications after replacing the bogies and electricals. It has different underframe for handling buffing loads.Some units are fitted with speed recorders and some changes to control electricals. Some units also have data recorders for energy consumptions.

                        415volts,3 phase,50Hz power supply is used to drive various auxiliary motors like 1)Traction motor blowers, 2)Transformer radiator blower, 3)Transformer oil pump, 4)Smoothing reactor blowers, 5)Silicon rectifier blowers, 6)Battery charges.The 3 phase, 415 volts is obtained from single phase supply by Arno converter or static converter.

                         WAP-4 have a maximum speed of 140kmph(service) and 160kmph(test runs).The braking system used is graduated air braking system.The loco and train braking both uses air braking system.Some newly introduced WAP-4 have air conditioning for the comfort of the loco pilots.