Railroad Bridge Dynamics and Ratings

TRB’s Safety Innovations Deserving Exploratory Analysis (IDEA) Program Final Report for Safety-IDEA Project 24: Railroad Bridge Dynamics and Ratings describes research that investigated train impact factors on bridges for speeds above 90 mph to be used in capacity ratings of existing bridges.

Bridge rating calculations are performed to determine the safe capacity of existing structures. The American Railway Engineering and Maintenance-of-Way Association (AREMA) Manual for Railway Engineering (MRE) is the current recommended practice used by the great majority of railroads in North America. The Foreword to MRE Chapter 15, “Steel Structures,” limits the application of the chapter to freight train speeds of up to 70 mph, and passenger train speeds of up to 90 mph. Therefore, the chapter provisions do not provide a method to calculate a bridge rating for train speeds beyond 90 mph.