Field study using additional rails and an approach slab as a transition zone from slab track to the ballasted track

Abstract

An abrupt change in the stiffness of railway tracks at the junction between slab track and ballasted track causes increased dynamic loads, asymmetric settlements, damage of track components, and, consequently, increased maintenance costs. Due to this, a transition zone is usually built at the junction between the ballasted and the ballastless tracks to reduce the aforementioned problems. One of the methods suggested as a transition zone in these areas is to use a combination of an approach slab and additional rails. This study evaluates the dynamic behavior of this type of transition zone using field tests and also compares its performance with a transition zone built only with an approach slab. Hence, in the Tehran–Karaj railway line, two types of transition zones were constructed: one including only the approach slab and the other one including additional rails and an approach slab. Then, by conducting some field tests, the dynamic behavior of the track in these two types of transition zones was examined. The results of the field measurements show that for the analyzed case study, at the combined transition zone with additional rails and an approach slab, instead of a sudden increase in rail displacements from the slab track to the ballasted track (i.e. by 53%), initially, in the first part of the transition zone (with additional rails and an approach slab), the deflections increase by an average of 31%, and then in the second part of the transition zone (with additional rails only) the deflections increase additionally by 11%.

The effect of soil improvement and auxiliary rails at railway track transition zones

“…The numerical results are also validated against field test data on the Tehran-Karaj railway line in Iran [67]. Field data were collected at a transition zone from a slab track inside a tunnel to a ballasted track at the entrance/exit.…”

“…Summary of track geometry data and material properties for ballasted and slab track component of transition zones [30,67]. a Half-length due to the symmetry in Z-axis.…”

“…Summary of track geometry data and material properties for common track structure of transition zones[30,67].…”

Monitoring and Expertise of Sections with a Sudden Change in Railway Track Stiffness—Transition Zones of Bridges

“…; Esmaeili, M.; and Varandas, JN. [2] using additional rails and an approach slab. High-speed lines depending on the train speeds were part of the dynamic characteristics of a fixed reinforcedconcrete track, published by authors Park, S.; Kim, JY.…”