A tie plate, also known as base plate or sole plate, which is a steel plate that used between the steel rail and railway sleeper. Tie plate basically has some holes and shoulder(s). But there is no shoulder in some types of tie plate. Rail tie plate usually has tapered side to improve the stability and reduce the twisting and torsion of rails. There are close relationship between rail and tie plate. Each tie plate is generally made for corresponding size of rail. In another words, the tie plate has to be matched with width of steel rail. As for the production process, tie plate can be made by three processing ways: hot-rolled, casted and forged.

As one of the railroad components, tie plate is used to fix rail to railroad tie and keep the rail safe. To be specific, the functions of railroad tie plate as follow:

Tie plates transmit the load from steel rail to the railroad ties. They provide even support surface for rail and prevent rail from movement.

Tie plate helps the rail maintain their gauge, which keep the safety of train running.

Tie plate reduce the friction between rail and railroad tie.

Tie plate protect railroad ties from excessive wear, so that prolong their service life.

Tie plate provide proper cant and bear the central load.

Continuous sole plates

Length: Standard 5,980mm.

Width: varies between 150 and 500 mm.

Thickness: between 12 and 50 mm; the foundation of the rail is decisive.

Material: S235JR, S275JR, S355J0.

Discontinuous sole plates

Length: between 150 and 300 mm.

Width: varies between 150 and 500 mm.

Thickness: varies between 12 and 50 mm, the base of the rail plays a decisive role.

Material: S235JR, S275JR, S355J0.

Ribbed base plates

Ribbed base plates have traditionally been developed for special applications such as tracks, switches and derailment safety devices, track shells or bridges.