Page:Derailment of Amtrak Passenger Train 188 Philadelphia, Pennsylvania May 12, 2015.djvu/37

NTSB implemented, compartmentalization is focused on preventing occupants from being thrown forward and away from their immediate seating area.

In this accident, the occupants experienced complex forward and lateral motions and forces. At least one passenger car, and likely more, overturned early in the accident sequence between the point of derailment and catenary support structure N121. This overturning would have resulted in occupants being thrown across the width of the rail car and striking the sides of the seats and sidewalls causing many passenger injuries. Therefore, the NTSB concludes that passengers were seriously injured by being thrown from their seats when the passenger cars overturned.

As noted above, 49 CFR Part 238 contains the current safety requirements for passenger railroad equipment. Those regulations include standards intended to minimize the effects of collision crash forces by trying to ensure that occupant space is preserved (structural crashworthiness) and that interior fittings such as seats remain secure (interior crashworthiness). To study these standards, the FRA has sponsored full-scale collision testing with conventional and crash energy management equipment. This research for passenger car crashworthiness has focused on in-line collision scenarios and the occupant response to the initial collision impact. Although this scenario is representative of some accidents, it is not representative of the full spectrum of accidents, such as derailments. The effects of derailments and passenger car overturns on occupants and the associated injury mechanisms have not been extensively studied.

Passenger equipment safety regulations did not even exist prior to 1999, and the NTSB acknowledges the progress in passenger car design that has been made in the past two decades. These safety standards, however, should not remain static and permanent because they may not provide protection to occupants in otherwise survivable derailments with passenger car overturns. According to postaccident interviews, in this accident many occupants were injured because they were thrown laterally and not compartmentalized. Others were injured because they were struck by luggage, seats, or other people.

The NTSB notes that in the case of highway vehicles, occupant protection standards have evolved to reflect current knowledge of crash dynamics. For example, the NTSB has recognized that in the case of school buses, compartmentalization is an incomplete solution, and seat belts are beneficial in preventing injury, especially in lateral impacts and rollovers.

The railcars involved in this accident were manufactured in the 1970s and, therefore, were not subject to the current passenger equipment safety regulations. But even if they had been built to meet the current standards, they would not have been required to provide protection from 27