Walking in the Lane

Riding to the shop nearby, have to cross a track on the way. Stop at the signal for the train to pass by. Noticing random things and questioning why?

About what all? One among them is- Have you ever noticed a gap between the railway tracks?

Looks like the train moves straight with no interruption. Ain't it?

Railway tracks are made up of steel, an alloy of iron , carbon and other materials. Steel expands on heating and it contracts on cooling. They get exposed to Sun: the ball of heat and light. These tracks are made up of rails joined together by fishplate.

A fishplate, or joint bar, is a flat metal piece that helps in connecting the rails. These rails are joined together with a gap between them. Do you wonder why? If the rails are joined without gap, the rail expand and bend due to the heat of the Sun. The expansion of material due to heat is called thermal expansion. The bend can lead to train accidents.

To avoid this catastrophe, the rails are connected to one another with a small gap. These gaps make the rail ends to expand due to heat and continuous friction of train wheels.

The expansion of rails are common during summer. But a major problem of joined bars is the cracking around bolt holes and produces clickety- clack sound.