Train-to-Train Impact Test of Crash Energy Management Passenger Rail Equipment: Occupant Experiments
Authors: Severson Kristine J. , Parent Daniel P. 
Published: April 2008

As part of an ongoing passenger rail crashworthiness effort, a full-scale impact test of a train with crash energy management (CEM) passenger cars was conducted on March 23, 2006. In this test, a train made up of a CEM cab car, four CEM coach cars, and a locomotive impacted a stationary train of similar mass at 30.8 mph. This test included five occupant experiments on the cab car and the first coach car to evaluate occupant injury risk and seat/table performance during the collision using anthropomorphic devices (ATDs). Three occupant protection strategies were evaluated in these occupant experiments. Forward-facing intercity seats were modified to reduce the high head injury risk observed in a previous test. Prototype commuter seats, included in both forward-facing and rear-facing orientations, were designed to mitigate the consequences of higher decelerations in the lead two CEM cars. Improved workstation tables, tested with two different advanced ATDs, were designed to compartmentalize the occupants and reduce the upper abdominal injury risk to the occupants. Similar experiments were also conducted on the two-car impact test of CEM equipment [1]. The experiments described in this paper were conducted to evaluate the level of occupant protection provided by seats and tables that were specifically designed to improve crashworthiness. Pre-test analyses indicated that the occupant environment would be more severe for the CEM test than for the comparable test of conventional equipment. The environment in the leading cab car was predicted to be similar to a 12g, 250 millisecond triangular crash pulse. The environment in the first coach was predicted to be comparable to an 8g, 250 millisecond crash pulse. To aid the design of the occupant experiments, occupant response models were developed for each of the occupant experiments using MADYMO. These models were developed for the previous two-car CEM full-scale test and adapted to the newly designed commuter seats and tables. Predictions of the occupant response during the CEM train-to-train test were developed before the test. The models were subsequently fine-tuned to better agree with the test data, so that many different collision scenarios may be simulated. Most of the test results were similar to the pre-test predictions. The modified intercity seats successfully compartmentalized the occupants. The risk of both head and neck injury, however, were above the respective injury threshold values. In the forward-facing commuter seat experiment the impacted seat experienced a partial failure of the seat pedestal attachment, resulting in loss of compartmentalization. The attachment failures occurred because the seats weren't fabricated as designed. However, the occupants were still compartmentalized, and the injury criteria were within survivable levels. The rear-facing commuter seat experiment experienced a more significant failure of the seat pedestal attachment, resulting in a loss of compartmentalization. The attachment failures likely occurred because the seats were not fabricated as designed and the collision was slightly more severe than predicted. To assure that this failure mode is prevented in the future, a more robust attachment is currently being developed. It will be tested quasi-statically and dynamically to demonstrate its effectiveness. The improved workstation tables successfully compartmentalized the occupants while limiting the injury risk to acceptable levels.