Why does the Human body feel Electric shock? and in an Electric train during running , We don't feel any Shock ? why?

our body resistance is45 mili ohm

during train we have our safty  agaonst electrical chook

human resistant body is vary different according to age,salut amount ,status,weight,......so body  resistance different from one to anotherbut the all human have small resistance,that allow to current to pass throw itso human body is so conductivitybut train have good insulator and have earthing to prevent human from shock

there is different types of shocks that a human body could encounter but in general the effect of it may be divided into two basics. the first one is the effect of frequency which cause muscular contractions which include the inner organs such as heart and lung. the second effect is the thermal effect of the current which depend on the voltage value and the path of the shock current through the body and that cause tissue damage some of them are severe and permanent. and for your second question its a full different case as the electrical transportations are fully insulated and the power provided to the machines driving the vehicle is double and triple and more protected so there is no direct contact between the passenger in any way with the electrical power. hope i was helpful to you.

In Electrical, When circuit completes, current flow starts.

So if you make medium to complete the circuit, you don't feel electric shock.

But when you open the circuit though providing ground from your body you feel shock.

That why we don't feel shock in electric train.

Human body is a conductor, not an insulator, due to its desing it also contains90% water. Further our mass have high quantity of free electrons.

Electric train is designed with insulation, and electricity does not pass to passenger side.

Unfortunately our body is a pretty good conductor of electricity, The golden rule is Current takes the lowest resistant path if you have insulation to our feet as the circuit is not complete (wearing rubber footwear which doing some repairs is advisable as our footwear is a high resistance path not much current flows through our body).The electric train is well insulated from its electrical system.