Considerations in the Analysis of Conventional Railway Track Support System

An adequate engineering analysis of conventional railway track support system (CRTSS) requires the consideration of all the major components of the track support system. Past efforts in this area have not been satisfactory because of lack of proper materials characterization and very simplified modeling of the CRTSS. A finite element model has been developed that allows determination of the instantaneous elastic response of the CRTSS. Because of the complex three-dimensional geometry, the analytical modeling was divided into two stages: a longitudinal analysis stage and a transverse analysis stage. Stress-dependent material properties of the ballast, the subballast, and the subgrade obtained from repeated load triaxial tests can be used with the finite element model. The finite element model has been validated using the measured response at Section 9 of the Kansas Test Track. Good agreement was obtained between the measured response and that calculated using the finite element model.