Model-assisted probability of detection (MAPOD) is a method for evaluating the effectiveness of inspection processes. The Federal Railroad Administration (FRA), through a contract with ENSCO, Inc., researched the feasibility of applying the MAPOD approach to the inspection of track flaws. ENSCO researchers analyzed six types of track inspection to determine the feasibility of the MAPOD application. They found ultrasonic rail flaw detection to be the most feasible type of track inspection for MAPOD application. This was mainly because models are already available for computer simulation and a test facility already exists at the FRA’s Transportation Technology Center in Colorado.