Question

What is the stress in steel train rails if the segments are laid in contact?

Answer 1

But , for the second part - b) - I have not been able to understand how to approach the problem... What stress means in the context? What concept I need to take into account to solve this problem?

Answer 2

Suppose that, after you allowed them to freely expand thermally, you then applied compressive forces at their ends to squeeze them back down to their original lengths.