Influence of Track Support Stiffness of Railway Tracks on Track Impact Factor

摘要

Track support stiffness (TSS) is used as a quality index of railway tracks to assess their performance and bearing capacity. TSS depends on the elastic stiffness of the elastic materials and the structural characteristics of the track system. The theoretically designed track impact factor (TIF), which is used to design ballasted and slab tracks in the Republic of Korea, is not detailed enough to describe various track types and TSS. In this study, the relationship between the TSS and the TIF for various types of tracks currently employed in Korean urban transit was assessed by performing field tests using actual vehicles running along the service lines. Field tests were performed on ballasted tracks (with good and bad ballast conditions) and three slab track types (i.e., sleeper-embedded track, rail floating track, and sleeper floating track). The theoretically designed TIF and TSS were compared with the corresponding TIF and TSS measured through field tests for the various track types on the service line. The condition of ballast (gravel) and the spring stiffness of the rail support materials directly affected the TSS. Moreover, the TIF for the service line appeared to increase with the TSS; therefore, it was inferred that the TSS directly affected the TIF.