Electrical Engineering Main and Traction Power for Passenger Trains

Can someone provide me further info on power to passenger trains like diagram showing how the dc 1500v / 900a travels from ohw/pantograph to main power/eaps/traction inverter/bogie motors and then further to earth/return current bars and axle brushes and then finally to rail. I want to understand how the circuit for current flow is completed for electrical auxiliary power supply (eaps) and traction power supply. Thanks and regards, muhammad jawad civil engineer senior planner in rolling stock manufacturing