Development of Performance Requirements for a Rail Passenger Workstation Table Safety Standard

Abstract

The American Public Transportation Association's (APTA) Construction and Structural committee, a railroad industry group, with the support of the Federal Railroad Administration (FRA) and the John A. Volpe National Transportation Systems Center (Volpe Center), is creating an industry safety standard for an energy absorbing table. Workstation tables in passenger trains are an increasingly popular seating configuration both in the United States and abroad. Although a well-attached table can provide convenience and compartmentalization for the occupant, there is a risk of abdominal injury during a rail accident.In Fact, there have been several accidents in the United States in which impacts with workstation tables have severely or fatally injured occupants. In 2006, in response to these injuries, an FRA sponsored program developed a prototype table that distributed load over a wider area of the abdomen and absorbed energy during a collision. This table design was tested with specialized anthropomorphic test devices (ATDs) instrumented to measure abdominal impact response and was shown to decrease injury risk compared to a baseline table design.Building on the knowledge gained in the development of the prototype table, the proposed standard requires force to the abdomen be limited while energy is absorbed by the table. Since manufacturers do not have access specialized ATDs, , researchers proposed a two part testing requirement. The first part is a quasi-static test which measures the energy absorption capacity of the table with a maximum force level determined from testing with specialized abdominal ATDs. The second part is a sled test with a standard Hybrid III 50 th percentile (HIII) ATD to assess compliance with occupant protection standards of compartmentalization and ATD injury assessment reference values (IARVs).This paper discusses the research performed to develop the performance requirement in the draft standard. Current injury measures, originally developed for the automotive industry, were examined to assess their applicability to workstation table impacts.Multiple Mathematical Dynamic Models (MADYMO) model simulations show the estimated injuries during a simulated sled test scenario. Several force-crush parameters were examined, including the initial stiffness of the force-crush curve, the plateau force and the target energy absorbed by the table, to determined the force-crush design characteristics of a table that are likely to reduce injury risk.

Evaluation of Testing Methods to Develop Test Requirements for a Workstation Table Safety Standard

“…The results of this modeling, which are described in the companion paper [8], indicate that kinetic energy absorbed by the table provides a meaningful correlation with abdominal injury. Generally, abdominal injury indices decrease as energy absorbed via table crush increases, provided that the peak contact force between the ATD and the table is limited.…”

“…The test conditions, test measurements, and performance requirements have been defined for each test. The rationale behind the specific performance requirements for each set of test requirements are explained in detail in the previously mentioned companion paper [8]. These test and performance requirements have been proposed in a draft industry table standard.…”

“…The rest of this paper focuses on identifying surrogate testing techniques that could be used in lieu a specialized ATD like THOR, but would still provide dependable, repeatable measures of Copyright © 2010 by ASME in a companion paper [8]. The results of these two papers have been used to draft an industry table standard.…”

Finite Element Analysis of the Passenger Rail Equipment Workstation Table Sled Test

“…The APTA table standard for passenger railroad equipment [2] was first published in March 2013. The performance requirements in the APTA standard are based on quasi-static and dynamic [5] test results using an FRA prototype table, and sled test simulations [6] conducted using MADYMO (a multibody system solver distributed by TASS International) [7]. Subsequently, railroad operators started to include the standard in their technical specifications for new equipment procurements.…”

“…At each seat position, the quasi-static test has an energy absorption requirement of 706 J (6,250 in-lbf) with a load limit of 10 kN (2,250 lb f ). The energy absorption and load limit requirements were developed from the results of a previous parametric study [6]. Options A and B are intended to provide equivalent safety.…”