Frost heaving

Frost heaving in railway traffic - The biggest problem the track bed encounters in winter is frost. The water that has been absorbed in the ground freezes in the cold weather, and the ground gets harder, and changes shape. Ground freeze creates problems and damages the track when the ground surface elevates under it. The elevation changes from one point to another, and this unevenness results in changed track geometry. This is called frost heaving.

Trains need to slow down because of the frozen ground. One way to prevent ground freeze damage is to build a layered track bed. Finnish railway has seven different layers of ground or insulator under the tracks.