Rails are a key component of any track system.

A contact surface the size of a small coin is exposed to enormous dynamic forces from the moving train wheels. Over their lifetime rails must be strong enough to withstand hundreds of millions of tonnes of rail stock, they must also be flexible enough to deal with constant load changes.

They therefore are exposed to some of the toughest conditions faced by all steel products, and dire consequences should they fail -gravely endangering people and property.