The Federal Railroad Administration (FRA) released its final rule governing the structural capacity of cab cars and multiple-unit locomotives to withstand head-on impacts. Such cars incorporate an engineer’s cab and passenger compartment for use as the lead car in a passenger consist. Because trains configured with leading cab cars or multiple-unit locomotives have no traditional locomotive in the lead, the lead car must be able to withstand a head-on collision. The final rule is based on structural modeling and full-scale field testing and requires the equipment to absorb collision energy and maintain sufficient integrity in crashes of a specified magnitude and speed to protect the interior space of the car. The final rule applies to cab cars and multiple-unit locomotives in service at speeds not exceeding 125 mph. The FRA rejected analogous European crashworthiness standards as inapplicable because of the lighter weight and differing collision characteristics used to formulate the European rule.