Each of us periodically encounters the work of railway transport. And the first thing that comes to mind with the word “train” is the rhythmic knock of wheels. He calms and soothes many people.

But few know why the wheels of a train knock. They are round, and must move silently.

The reason for the knocking wheels

The railway is built from separate sections of rails, as a children's designer. To create a continuous smooth canvas is not difficult at all, but the reason is different. It is impossible to build metal rails close to each other, because in the heat the metal expands, and in the cold, on the contrary, narrows. This applies to all countries in which summer and winter are pronounced. The rails are connected to each other using thermal clearances. So they serve much longer.

Rhythmic tapping occurs at the joints of individual sections of the rails, even if there is a minimum gap between them. The cars seem to jump onto the next section of the rail, which causes a rhythmic knock.

Silent Train Movement

There is.Such rails are called “jointless”, and are found in countries for which high temperature differences are uncharacteristic. They do not have thermal gaps, this is a continuous smooth canvas. Therefore, the cars do not knock, moving on rails.

The answer to the question “Why train wheels knock” is simple. This occurs when the train runs into individual joints of the rail. In countries where there are large plus and minus temperatures, it is impossible to build a smooth “jointless” rail track. But, let's say, in Australia, the wheels of the train do not knock.