Factors Affecting the Performance of Railway Track Substructures in Seasonally Cold Climates

Abstract

Assessing the performance of railway track structures in Finland has become increasingly important as engineers seek to develop improved designs and more effective maintenance and rehabilitation strategies that improve safety, increase service life, and reduce life-cycle costs. Through extensive research, several factors affecting the performance of railway track substructures have been identified and studied. The purpose of this paper is to provide an overview of the main research findings and recommendations pertaining to ballast, sub-ballast, frost action, and track stiffness and embankment stability. While material specifications, design procedures, and construction methods have been developed to ensure adequate performance of track substructures in new construction, special challenges exist with respect to managing existing tracks that were not designed for modern conditions. Safety and riding quality demands mandate high smoothness from high-speed tracks and set high standards for track construction and maintenance, especially on mixed-traffic lines where heavy freight trains are also loading the track. In addition, humid and cold winters and very weak subsoils in many areas add complexity to the problem.