Vertical load distribution in ballasted railway tracks with steel slag and limestone ballasts

Abstract

Over the last few years, use of steel slag ballast as an appropriate material instead of conventional stone ballast has gotten more attention by railway owners in various countries. In this regard, one of the technical concerns is the differences of vertical load distribution in these two materials. This factor has a significant influence on track safety and performance. In the present study, the behaviour of both kinds of ballast materials under vertical loading has been compared using a 50-meters test track including separate parts of both ballast materials. Rail support modulus and contact pressure of sleepers and ballast were obtained via a series of field tests. In order to determine the rail support modulus, the modified Talbot method has been used. The track was loaded by both light and heavy six-axle car bodies with 300 and 1350 kN weights, respectively; furthermore, a specific sleeper which was equipped by load cells was used to measure the contact pressure of sleepers and ballast under mentioned heavy car body in both types of ballast material. Results show that, with the same track superstructure and subgrade condition, the rail support modulus of test track in steel slag ballast section is 1.64 times greater than that of limestone ballast, and the compressive contact pressure of sleeper and ballast in limestone ballast was almost 1.39 times greater than steel slag ballast.