Question

How are railway lines protected from rust by electric current?

Answer 1

Compared with the steel used for buildings, the steel in a rail is composed of a higher quality steel alloy, which is less susceptible to corrosion. This is necessary as the rail will be subjected to much higher dynamic stresses than the steel in a building frame. A steel rail also has a thicker cross-section. When the rust forms on the face of the rail it acts as a barrier which then slows the rate of corrosion.