Railroads actively manage rail life based on a number of factors and in this Technology Digest, MxV Rail documents some scientific approaches available to help railroads optimize their maintenance plans. Rail is one of the primary assets for railroad operators. Every year, railroads in North America spend millions of dollars for rail replacement primarily due to either rail wear or rail and weld breaks caused by fatigue defects. Different factors affecting track and rail life have been considered in statistical and mechanistic models to predict rail life so railroads can make effective labor and budegtary plans for rail replacement. Over the last 30 years, many scientific approaches have been used to create models and methods to predict rail life as a function of wear or fatigue or both.1,2 One concept of rail integrity as a function of rail strength is based on the Strength of Materials (SOM) approach where the…