Characterization of the loading environment for shared-use railway superstructure in North America

A sustained increase in heavy axle loads and cumulative freight tonnages, coupled with increased development of high speed passenger rail, is placing an increasing demand on railway infrastructure. Some of the most critical areas of the infrastructure in need of further research are track components used in high speed passenger, heavy haul, and shared infrastructure applications. In North America, many design guidelines for these systems use historical wheel loads and design factors that may not necessarily be representative of those seen on rail networks today. Without a clear understanding of the nature of these loads, it is impossible to adequately evaluate the superstructure to make design improvements. Therefore, researchers at the University of Illinois at Urbana-Champaign (UIUC) are conducting research to lay the groundwork for an improved and thorough understanding of the loading environment entering the track structure. Multiple wheel load measurement technologies have been used historically to monitor vehicle health by measuring and recording information related to vertical, lateral, and longitudinal loading. This information can be used to identify and classify trends in the loading spectrum and other characteristics of the rolling stock. These trends not only provide a clearer picture of the existing loading environment created by widely varied traffic characteristics, but can be used in future design and maintenance planning activities according to the anticipated traffic. This thesis will discuss the current trends in the loading environment across the North American rail network while investigating the effects of speed and other sources of variability. Ultimately this work should lead to useful distinctions of loads for evaluating and improving design methodologies that are based on current loading conditions.