Citation

Sarunac R, Zeolla N. Transp. Res. Circular 2003; (E-C058): 89-103.

Copyright

(Copyright © 2003, U.S. National Academy of Sciences Transportation Research Board)

DOI

unavailable

PMID

unavailable

Abstract

This study explores the option of integrating a low-floor extension (LFE) module into the existing light rail vehicle to augment current service with low-floor boarding and simultaneously to increase passenger capacity. In an effort to minimize the overall weight of the LFE, this study examines two feasible approaches for specifying the longitudinal strength of the LFE that are consistent with current industry practice. The two alternatives considered are the "strength-based approach" and the "energy-based approach." The de facto industry practice is a strength-based approach where the buff strength is specified to meet two times the AWO weight of the vehicle, commonly referred to as the "2-g buff load." The feasibility of an alternative approach, using crash energy management (CEM) principles to limit the longitudinal loads in a controlled manner, was also examined in detail. In a collision, the CEM zone would generate predetermined peak and average reaction loads, thereby limiting the longitudinal load transmitted to the LFE, while still meeting minimum static strength values. These zones would be designed to deform or crush in a controlled manner, thereby absorbing collision energy and minimizing the potential for deformation and acceleration in the passenger compartment. Since structural strength is fundamental to passenger safety, the new structure of the LFE module and any modifications made to the existing vehicle must meet the same structural standards used originally or must provide an equivalent level of performance in a collision. For this study, collision performance is being measured only in terms of peak and average accelerations and deformation.