Question

how the problem of expansion is overcome in railway line bridge and oil pipes​

Answer 1

Answer:

Bridges normally have expansion joints built in so that as the material changes from heat, for example, the change is absorbed without disturbing the surface. Suppose a bridge could be built with rigid material so that expansion is absorbed by a hinge action in the middle of the bridge. The ends are firmly anchored at A and C. Let the bridge be one mile (5280 ft) long.

If the coefficient of expansion is (1/2640) the bridge surface would increase in length by 2 ft.