Usually, the wheels have a lip or flange that sits inside each rail and keeps the train on the track. The wheels are made of steel so that trains can carry heavy weights at high speeds. In the past, tracks were laid in short sections, and train passengers could often hear the click of the wheels as they ran from one section to another. Modern track-laying vehicles weld the track into one continuous rail to give a smooth ride. The tracks are usually supported on beams of wood or concrete called sleepers.
Trains change track at points.
Engines and carriages Nearly all trains have a locomotive to provide the power and a series of carriages for carrying passengers or trucks for carrying goods. The first locomotives were steam-powered. These burned coal to boil water into steam to drive the wheels. Diesel trains carry their fuel with them. Electric trains pick up power either from a live rail lying parallel to the track and called the third rail, or through an arm called a pantograph from overhead cables.