Fastening systems

A rail fastening system is a means for fixing rails to railway track sleepers. The duty of the rail fastening system is to assure stable but at the same time flexible connection between the rails and the supporting cross sleepers in the railway track.

According to the mode of fastening, rail fastening systems may apply a) direct fastening of the rail to the sleeper with or without a base plate between the two of them, by spikes or sleeper screws, or b) indirect (separated) mode of fastening when the base plate is fixed to the sleeper by sleeper screws while the rail is fixed to the base plate by either clamp plates and bolts with nuts or flexible clips / tension clamps and bolts with nuts. A flexible insulation plate (pad) made of rubber or plastic is frequently applied between the bottom of the rails and the base plate which serves double purposes: to provide an increased flexibility of the fastening system and to insulate the electrically conductive rail.

Nowadays the indirect fastening modes are in overwhelming majority of railway tracks applied. In Hungary two types of fastening systems are wide-spread: the rigid mode of fastening by clamp plates called in Hungary GEO (Gesellschaft für Eisenbahn Oberbau) fastening system known in Germany as Oberbau K (superstructure K), and the flexible mode of fastening for which primarily W14 fastening system is used with tension clamp SKL-14.