Question

Why we feel the train in which we are sitting appears to move while it is at rest

Answer 1

because of inertia......

Answer 2

Yess… I am aware of that feeling

It happens only when you look out of the window and another train is running in the direction opposite to your train. So it feels like your train is moving although it is not.

Just a game of mind nothing else.

Moreover this feeling only persists for a short period of time untill you realise what is actually happening.