Wheelchair occupant kinematics during a rail carriage crash

Abstract

Over recent years, a number of legislative tools and codes of practice have been put in place to provide wheelchair users with greater access and freedom of using trains. However, much more is still needed to be done to improve the safety of wheelchair occupants (WOs) while on board. In the United Kingdom, under the Disability Discrimination Act, only approved dimensions are the minimum requirements for use of a wheelchair in a rail carriage. This paper seeks to provide an analysis of the experimental kinematics of a WO under frontal impact tests carried out using a 57 kg dummy subjected to a sudden stop generating a pulse of about 15 g, which is less than the ECE M1 vehicle category. However, this is more severe than the 5 g pulse that covers both the European Commission's TSI and prEN 15227 with regards to train crashes. Results of frontal impacts are presented where the resulting kinematic characteristics are used to assess the potential injury severity of the occupant. A loaded sled with a combined mass of about 200 kg was accelerated horizontally to 3.3 m/s and suddenly stopped using a rigid barrier to simulate the worst loading condition. Eight restraint scenarios are covered. These form the basis for making recommendations considering the safety of a WO during a crash of a rail carriage. The baseline scenario constitutes not securing the wheelchair and not restraining the occupant. This also represents the worst case for injury potential. The ideal scenario involves securing the wheelchair and restraining the occupant using a three-point occupant restraint system. The paper concludes by providing recommendations for seating configurations to improve the survivability of a WO during a crash in a railway vehicle.