Railway track
A railway track or railway line is a set of two parallel rows of long pieces of steel. They are used by trains to transport people and things from one place to another. (In America, people say railroad as well as railway). Often, there is more than one set of tracks on the railway line. For example, trains go east on one track and west on the other one.
The rails are supported by cross pieces set at regular intervals (called sleepers or ties), which spread the high pressure load imposed by the train wheels into the ground. They also maintain the rails at a fixed distance apart (called the gauge). Ties are usually made from either wood or concrete. These often rest on ballast, which is a name for very small pieces of broken up rock that are packed together and keep the railway tracks in place. Tracks are often made better by ballast tampers.
The upper surfaces of the rails are inclined slightly towards each other, typically on a slope of 1/20, and the rims of the train wheels are angled in the same way ("coning"). This helps guide the vehicles of the train along the track. Each wheel also has a flange, which sticks out from one edge all the way around. This makes sure the train does not "derail" (come off the track) and helps guide the train on sharp curves.
