Criteria and procedures have been developed for assessing crashworthiness and occupant protection performance of alternatively designed train sets to be used in Tier I(not exceeding 125 mph) passenger service. These criteria and procedures take advantage of the latest technology in rail equipment crashworthiness and include aspects that are fundamentally different from current regulations, such as the scenario-based train-level requirements, which have no counterpart in FRA's current Tier I regulations. Numerical values of the pass/fail criteria have been selected to provide an equivalent level of crashworthiness as the current Tier I regulations.