Sleepers, also known as sleepers, are also a kind of railway accessories. It's just that the material used is not just wood, so it is more scientific to call it sleepers.
Don't look at the appearance of the sleeper monotonous, the appearance is not amazing, its role is not small. The sleeper must not only support the rail, but also maintain the position of the rail, and transfer the huge pressure transmitted by the rail to the track bed. It must have a certain degree of flexibility and elasticity, hard or soft. As the train passes, it can be deformed appropriately to cushion the pressure, but it must be restored as much as possible after the train passes.