The rail must provide a continuous, smooth, and least resistant rolling surface for the wheel. In electrified railway or automatic block section, rail can also be used as track circuit.
Rail is the main component of railway track. Its function is to guide the wheel of the rolling stock, to bear the great pressure of the wheel and to deliver it to the sleeper.
Rails are used as signal return lines, so insulation must be made to prevent stray current interference.
