Rail fastening system is composed of rail fastenings. Rail fastenings are used to connect rail and railway sleeper. The main function of rail fastening system is fixing rail on the railway sleeper. The common rail fastening include rail spike with base plate above the tie, E-clip Fastening, Pandrol Fast Clip Fastening, Tension Clamp Fastening, Bolt Clamp Fastening, Tack Joint and Chairs Fastening, and Steel Spring Keyed rail in Chair Fastening. For passenger railway line, comfort and reliability is major goal. Ballastless track laying not only refers to substructure, including bridge, tunnel and subgrade, etc. The key techniques for rail fastening system are the necessary condition for railway operation.
The passenger railway generally adopt ballastless track, which requires better elasticity of rail fastening system compared to ballast track. Elasticity of rail fastening system can’t be increased without limit. Otherwise it will have influence on smoothness of rail. So Balance rigidity of rail fastening and rail safety is one of the key techniques for rail fastening system.
According to requirement of track circuit, rail fastening system must have good insulation property in the dry-wet-cycle condition. So that key techniques for rail fastening system is required to improve water resistor.
Ballastless track structures vary, but from the view of design, construction and operation management, it requires rail fastening system has versatility. Both sleepers buried ballastless track and slab ballastless track can use one rail fastening system together. Key techniques for rail fastening system include fitting various ballastless track structures.
The rigidity of rail pad decrease, which means rail pad have large deformation during train passing. At the same time, front of rail clip have bigger dynamic deformation. It has higher need on elastic property and fatigue property of rail clip. When low-rigidity rail pad applied, the key technique is control crimping force loss and fatigue life of rail clip.
Ballastless track usually adopt elastic separated rail fastening (with a tie plate). According to functional need, tie plate is fastened on the concrete foundation through anchor bolt and rail plastic dowel cooperation (which is pre-imbeded into the concrete). Based on experience, strength and fatigue life of embedded parts in construction is a weak link. Improve the strength and fatigue life is one of the key techniques need to be solved.
Summarizing experience on ballastless track, adjustment amount of rail location is large and accurate. In conclusion, good rail fastening system has less spare parts and adopt easy operation mode to adjust rail position. When the left and right side is adjusted, try to avoid changing fastening. Stepless adjusting will be the best adjusting mode.