Why Modern Rails Have No Room to Expand

Modern railway track is welded into ribbons of steel that run for miles without a single gap, and steel expands when it gets hot. By that logic, the track under every summer train should push itself sideways off the ground. Mostly, it doesn't. This is the engineering that holds back more than a hundred tonnes of force in a single rail, the neutral temperature, the ballast, the clips and anchors, and what happens on the days it loses: the sun kink.