Abstract A railway infrastructure capable of supporting a high frequency of light and heavy traffic, sometimes at high speed, requires the implementation of a high quality track. A correct definition of all track components leads to a high degree of safety and comfort for travelers as well as reduced operating costs. One factor that determines the elastic behaviour of the track is the rail fastening system. In this paper, the mechanical, electrical, and environmental sustainability characterization tests based on European standards UNE-EN have been carried out, verifying that the TK04 fastening system with a lateral adjustment of ±1 cm, manufactured by ThyssenKrupp Gleistechnik GmbH, satisfies the conditions and requirements of European standards UNE-EN for installation on slab track systems for light rail.