eli5 Why do trains with steel wheels have traction on steel rails, but if your brakes on your car are used up and become steel on steel they dont work anymore?

Question

eli5 Why do trains with steel wheels have traction on steel rails, but if your brakes on your car are used up and become steel on steel they dont work anymore?

In: 1231

Answer 1

[Practical Engineering on YouTube just released a video talking about this](https://www.youtube.com/watch?v=Nteyw40i9So).

Summary:

* steel rails last longer
* steel wheels have less friction and can carry more weight

Train wheels and rails both have to be replaced periodically, just like the brakes in your car.