Mechanics-based model to predict ballast-related maintenance timing and costs

A mechanics-based model has been developed which predicts the timing of required ballast maintenance based on track settlement and roughness. With user-defined track material properties, loading characteristics, and maintenance technique to be applied, the model determines the rate of track roughness increase and applies the desired maintenance when such roughness exceeds a limit. This analysis is continued, usually over the life of the ballast, and the related life cycle cost is calculated. For another ballast material or maintenance technique, a lower or higher cost may be realized. In this way, the model user may observe the effect upon ballast maintenance and cost of using concrete rather than wood ties, a heavier axle load, or increasing the track stiffness. Because the life cycle cost is used, the frequent mistake of determining purchasing decisions based upon the least cost in the present is avoided. Instead, the model allows the user to optimize by considering the associated costs incurred during the component life