How can trains move on rails? if the wheels are smooth and the rails are also smooth, how can it be enough friction for it to move?

Question

How can trains move on rails? if the wheels are smooth and the rails are also smooth, how can it be enough friction for it to move?

In: 2785

Answer 1

You can place a penny on the track and it will be literally [flattened](https://qph.cf2.quoracdn.net/main-qimg-a0bac7993cbd3ff14b8deb69aebb47ce-lq) by the train. That train is constantly trying to flatten that rail too – that’s all the friction you need.