6. Conclusions

The increase in speed and the improvements in comfort and safety experienced by the high-speed train in recent decades are the result of the engineering innovations implemented in this means of transportation. In this chapter, the studies developed by the LADICIM research group on the design of the fastening system between the sleeper and the rail have been examined. Once verified that the fastening system selected for the high-speed line between Madrid and Barcelona fulfills the requirements of the European standards EN 13146, this contribution focuses on the experimental results derived from the characterization of each of its components. The conclusions drawn from this research are summarized hereafter:

• Guide plate

Increasing the moisture content reduces the strength and increases the deformability of the plate. This reduces the static force to be applied to provoke the contact with the screw. In case of an impact, the plate fails before contacting the screw, and fracture occurs with greater deformation and less force when the moisture content increases. This increase also causes a decrease in fatigue resistance.

The increase of the tightening torque applied to the system raises the force required to achieve the plate-screw contact under static conditions, reduces the impact deformability, and increases the resistance against fatigue.

A plate tested for 500,000 cycles has approximately the same behavior under static and impact conditions as an original plate.

• Seat pad

Temperature reduces the stiffness of the plate, both under quasi-static or dynamic conditions. The energy dissipated per cycle is accentuated by increasing the temperature.

Hardness correlates linearly with stiffness; then, hardness can be considered as an index of the degree of degradation undergone by the pad. This parameter is very useful as it can be easily measured by a nondestructive test on the track under inservice conditions.

Extreme temperature values on the railway track (−20 and 80°C) define the threshold working values for seat pads, both under dynamic and static conditions.

• Anchorage components

Increasing the humidity content of the dowel reduces the resistance under static, impact, and fatigue loading. Even in the worst scenario, this component fulfills the minimum requirements imposed by the European standard.

The screw subjected to saline fog chamber for 300 h shows a tensile behavior very similar to an original screw; the presence of a small notch does not reduce its mechanical resistance. In both cases, the screw survived to the bending test.

• Clip

The only difference between a used clip, a new one or one subjected to 300 h in a saline fog chamber lies in the first loading cycle; once the component is plasticized, the behavior is similar.

Optimization of Components of Superstructure of High-Speed Rail: The Spanish Experience DOI: http://dx.doi.org/10.5772/intechopen.80013
