Crash Energy Management Crush Zone Designs: Features, Functions, and Forms

Abstract

On March 23, 2006, a full-scale test was conducted on a passenger train retrofitted with newly developed cab and coach car crush zone designs. This test was conducted as part of a larger testing program to establish the degree of enhanced performance of alternative design strategies for passenger rail crashworthiness. The alternative design strategy is referred to as Crash Energy Management (CEM) where the collision energy is absorbed in defined unoccupied locations throughout the train in a controlled progressive manner. By controlling the deformations at critical locations, the CEM train is able to protect against two very dangerous modes of deformation: override and large scale lateral buckling.The CEM train impacted a standing locomotive-led train of equal mass at 30.8 mph on tangent track. The interactions at the colliding interface and between coupled interfaces performed as designed. Crush was pushed back to subsequent crush zones, and the moving passenger train remained in-line and upright on the tracks with minimal vertical and lateral motions.This paper evaluates the functional performance of the crush zone components during the CEM test. The paper discusses three areas of the CEM consist: the leading cab car end, which interacts with a standing locomotive; the coupled interfaces, which connect the CEM non-cab end; and the trailing cab car end, which interacts with the attached trailing locomotive. The paper includes a description of the crush zone features and performance.The pushback coupler must absorb energy in a controlled progressive manner and prevent lateral buckling by allowing the ends of the cars to come together. The deformable anticlimbers are required to resolve non-longitudinal loads into planar loads through the integrated end frame while minimizing the potential for override. The energy absorbers must absorb energy in a controlled progressive manner. The engineer's space must be preserved so that the engineer can ride out the event. The passenger space must be preserved so that the passengers can ride out the event. The prototype CEM design presented in this paper met all the functional design requirements. This paper describes how the crush zones perform at three different interfaces. Areas for potential improvements include the design of the primary energy absorbers, the placement of the engineer's compartment, and the interaction between the last coach car and the trailing locomotive.

Prototype Design of an Engineer Collision Protection System

“…The SIV measured in the cab of the lead car in the full scale crash energy management train-to-train test is included in the figure. This is a particularly harsh pulse because the crush zone elements were between the cab and the car body [6]. The SIV from a typical automobile crash pulse is also included in the figure.…”

Liquefied Natural Gas Tender Crashworthiness in Train-to-Train Collisions

“…For a cab car-to-locomotive collision of two passenger trains, equipment with CEM features can protect the passengers and crew for twice the collision speed as conventional equipment [14]. The performance of passenger equipment with CEM features has been measured and analyzed in detail [15,16,17]. This paper includes simplified engineering analysis of CEM features on LNG tenders.…”

“…Space limitations on the locomotive may inhibit the energy absorption capacity of the pushback coupler when a conventional draft gear is used; other elements, such as the deformable anti-climber and primary energy absorber, may be used to provide the needed energy absorption capacity. Engineering design, analysis, and test efforts, similar to those conducted for passenger equipment [15,16,17], may be necessary to develop prototype and service CEM features for LNG tenders that are service and crashworthiness compatible with existing freight locomotives.…”

“…FRA also developed a cab car deformable anti-climber design that maintains vertical and lateral load path and also meets traditional strength-based requirements [15,17]. This deformable anti-climber was also tested as part of the CEM trainto-train test.…”

“…The buff stops, which support the draft gear during normal operation, have been modified to fail at a prescribed impact load. These features were tested as part of the CEM trainto-train test [16,17]. In this test, a CEM cab car led passenger train collided with a conventional locomotive-led passenger train at 30 mph.…”