Why a person burns when overhead wire touched on train, Why doesn't he jerk - #TheGK by Pankaj Tiwari

The Overhead electric supply in trains is AC (25KV single phase) in nature not dc. But there is only one wire because the overhead wire is phase and track works as neutral as well as earth. 25 KV AC is converted to DC Using full wave rectifier then converted to 3-Phase AC to drive the motor in boggie. and the track works as neutral (return path for the current which is must either it is AC current or DC current). 

As far as person touching overhead wire mostly dies not because it sticks the person but because of very high voltage (25KV) that person instantly catches fire due to flashover 

The power supplied in homes is mostly single Phase AC (230 Volts). One wire is Phase and other is neutral. In bith wires current is always equal( due to law of conservation of charge) only the instantaneous value of current (and voltage) changes from positive peak to negative peak in same wire ( 50 cycles or 100 times polarity changes). 

Due to current value reaching zero while changing polarity , it gives mostly shock and person gets some time to move away from the wire.

Pankaj Tiwari

Electrical Engineer

PWD Department MP 

ex Engineer MPEB & Indian Railways