When the wheels of a train press on their rails the local stresses are transient but enormous.
This is apparently a high enough pressure to cause plastic, ie permanent, cumulative deformation as each wheel passes a given point.
Once a crack has been created, subsequent stress will cause it to propagate and the rail will eventually require replacement.
Today’s invention is intended to prolong the life of our hard-pressed railway lines. It takes the form of an extra electromechanical control system for a train’s suspension.
Each pair of train wheels would be capable of being raised slightly, allowing the weight of the train to be redistributed non-uniformly from instant to instant.
Positions where cracks had already occurred would be mapped so that as a train passed over, the pattern of weighting and unweighting could be rapidly altered in order to minimise the bending moment tending to open the top face of the rail, for example.
This could mean that most of the weight would be thrown onto the nearest two wheels to a crack, rather than the farther ones.