Because of its weight, a train is several thousand tons, which is too much for the expressway. The pressure on the train track is evenly distributed on the ballast by sleepers (increasing the area and reducing the pressure).

Because it is fast, the friction between train wheels and tracks is small, which improves the speed.

There are also some factors, such as the rail, which can turn the train around through the inclination of the rail and the inclination of the rim. In addition, the track reduces the floor space.

Many factors make it necessary for the train to walk on the track.

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