Scaling issues related to modeling of railroad car damage II-explosions, fires, and safety valves

This is a companion paper to “Scaling Issues Related to Modeling of Railroad Car Damage I” that addresses issues connected with scaled-model testing of railroad cars in serious accidents. The previous paper dealt with the mechanical issues occurring in an accident: derailment, plastic deformation of the rail cars, rupture of the cars, and the initial impact. In this paper, the associated results of railroad accidents are analyzed. The specific topics covered are fires, explosions, and damage to safety valves. As with the previous work, this paper is predicated on the fact that fullscale tests of railroad cars are for the most part prohibitively expensive. Small-scale models of trains are preferable, but the problems cannot be resized without having many other physical parameters scaled as well. This paper provides insight to the three damage mechanisms listed above. The ways to scale them are analyzed using the mathematical technique of dimensional analysis. Also identified are physical phenomena that do not lend themselves to easy rescaling.