Occupant Protection - current projects

Passenger Car Crashworthiness

The purpose of this project, initiated in 1995, is to develop safety assessment methods and assemble design data to improve the crashworthiness of passenger vehicles.  Advances in mathematical modeling methods are sought to bring the methodology up to the state-of-the-art in crash analysis, reflecting improvements in computing capabilities.  A series of analyses and tests, involving different collision scenarios, are used to verify the models and evaluate the possible changes of cab and car structures to improve the safety of crew and passengers. 

As part of this study, several design concepts of crash energy management (CEM) have been evaluated and one CEM design, engineered by using zones of controlled crush, was selected to improve crashworthiness performance over existing passenger car designs. This design causes the collision energy to be absorbed by a series of components with known structural characteristics. Passenger car with CEM installed is shown below. 

Passenger car with CEM end structures.

Passenger with CEM ends, showing primary energy absorbers.

Secondary collisions, such as within the cab car or within the passenger car, which result in passengers or crew striking the interior of the cab or car, can also be reduced in number and severity through ergonomic design and careful planning. Passenger “compartmentalization,” seat design and fastening, seat belts, strategic placement of equipment, hand hold designs, and ride quality enhancements during rapid starts and stops are among options under investigation.

This research includes dynamic modeling, simulations, component testing, and full-scale crash testing.  Advanced new models that reflect the state-of-the art in crash analyses were developed and used for the study. Other types of models were also developed. 

New CEM structural members were tested to evaluate their performance to deflect debris from collisions or absorb the crash energy in a safe manner.  A series of full-scale crash tests (see Table 1) were conducted at the TTC to verify the simulations and to demonstrate the effectiveness of proposed remedies.

Table 1. Full-Scale Impact Tests of Passenger Vehicles at TTC

Test Conditions	Conventional Design Equipment	Improved Crashworthiness  Design Equipment
Single-car impact with fixed barrier	November 16, 1999 Windows Media (363 KB)	December 3, 2003
Two-coupled-car impact with fixed barrier	April 4, 2000 Windows Media (361 KB)	February 26, 2004 ( photos (not available) ) Windows Media (570 KB)
Cab car-led train impact with locomotive-led train	January 31, 2002 Windows Media (378 KB)	March 2006 (tentative)
Single-car impact with steel coil	June 4, 2002 Windows Media (382 KB)	June 7, 2002  Windows Media (382 KB)

Sequence of crushes shown during full-scale impact tests of passenger cars with
conventional design (below, Nov 1999) and CEM design (above, Dec 2003).

video clip 1

video clip 2

A new research project on passenger car crashworthiness will investigate the dynamics of oblique or raking impacts resulting from non-rail vehicles colliding with passenger cars and cab cars, especially at grade crossings.  Emphasis will be placed on minimizing the effects of such collisions through the development and enforcement of passenger car and cab car structural standards for crashworthiness. 

The technical results of this projects is used to support the rulemaking efforts at the Office of Safety of FRA and those at APTA in the development of their safety and design practices in order to promote synergies between private and public efforts to develop safety standards.  One of the new initiatives is the safety assessment of joint operation of light rail vehicles (LRV) vehicles on tracks also used by freight and conventional passenger trains.  

Emergency Preparedness

This research is directed at the safe and efficient passenger rail car evacuations during various emergency scenarios. A goal is to determine if time-based evacuation criteria can replace existing prescriptive rules on the number and configuration of emergency exits. Studies will involve, as appropriate, emergency plans and procedures, training, emergency exits and access points, signs and instructions, and emergency lighting Emergency preparedness research will continue through FY 2006.

The two main objectives are the identification, testing and analysis of new technology; and the development of objective and cost-effective minimum performance criteria for emergency lighting levels, as well as conspicuity/visibility criteria for emergency exit and access signs.

A general set of recommended emergency preparedness guidelines were developed and published in 1993. The guidelines are intended to assist passenger train system operators to assess, develop, document, and improve their emergency response capabilities and to coordinate these efforts with emergency response organizations. It was used as the baseline resource document in the development of the Passenger Train Emergency Preparedness regulations issued in 1998 and the Passenger Equipment Safety Standards, issued in 1999.

In cooperation with the Massachusetts Bay Transportation Authority (MBTA, a series of commuter rail car egress tests was conducted in 2005 at North Station, Boston, MA. To FRA knowledge, this is the first time that egress trials were conducted using U.S. rail cars and passenger recruited from the general ridership. Human factors data related to the length of time necessary for passengers to exit a coach car to an adjacent car or to the station platform using one or two doors, under both normal and emergency lighting conditions was obtained. The exit time data are intended to be used as an input to the planned adaptation of a existing transportation computer egress model in order to predict emergency evacuation time. The objective of the egress model for rail car evacuation time prediction is to save time and money, as well as eliminate or minimize safety and health issues when compared to the logistics of using human test subjects to determine the minimum required.

People getting off the train

 
video computer screen

In addition, the FRA is constructing a “rollover rig” that will be used as a training tool for emergency responders to be located in at the WMTA Emergency Response Training Facility located in Landover, MD.

   
rollover rig

The rollover rig is based on a United Kingdom design and can simulate the position of rail cars that do not always remain upright in an accident. The frame of the rig will hold a NJT commuter rail car that can be rotated in a controlled manner up to 110 degrees from the upright position, using steel cables linked to a portable diesel engine. The rollover rig thus can be used to evaluate the effectiveness of various vehicle egress component in various types for emergencies.

The rollover rig is being fabricated during 2005 and is schedule for installation at the WMATA facility in mid-2006.

Passenger Car Fire Safety

This project supports the development of fire safety regulations for passenger equipment in both intercity and commuter rail services. A major conclusion of previous study was that the use of fire hazard and fire risk assessment supported by measurement methods based on heat release rate (HRR) could provide a means to better predict real world fire behavior. In addition, the FRA has no means to quantitatively measure the degree of additional fire safety provided by material fire safety performance or other fire protection requirements, such as fire detection and suppression, and emergency egress systems.

The purpose of this study, initiated in 1995, is to determine appropriate HRR performance criteria for component materials that will provide an equivalent or higher level of safety to the existing FRA-cited tests. Heat Release Rate (HRR) is defined as the amount of energy a material produces while burning. The fire hazard to passengers of materials can be directly correlated to the HRR of a real-world fire and also permits the evaluation of material interaction and interior geometry effects, as well as fire detection and suppression systems, and their effect on evacuation time.

To date, small scale HRR data for 30 materials used in Amtrak intercity rail cars has been obtained using a Cone Calorimeter test apparatus. In addition, HRR data was generated from real scale Furniture Calorimeter tests of component assemblies were conducted as well as and full-scale car tests. The HRR data has been used in a baseline analysis using a computer fire growth model to estimate the fire growth of different fire scenarios and ignition sources to determine available egress time for different types of car configurations.

Full scale Amtrak coach car seat trash bag fire test

The preliminary results of the research has been used in the development of Passenger Equipment Safety Standards issued by FRA in 1999 and amended in 2002.

Further results of the fire safety research program will be used to determine appropriate HRR performance criteria for component materials to provide an equivalent or higher level of safety to the existing FRA-cited tests.

The use of appropriate small-scale material HRR test data and verified fire computer models for the evaluation of rail vehicle fire safety is consistent with ongoing efforts to develop performance-based fire codes in the U.S. and Europe.

Safety on Non-Compliant Rail Vehicles

Commuter railroads and transit authorities anticipate continued growth in the demand for their services, and at the same time they face constraints in the availability of capital to construct new systems.  Consequently, they view the use of existing railroad tracks as a key element of their strategy to initiate new commuter rail services with the lowest possible capital outlay.  To keep capital and operating costs for rolling stock low, commuter railroads and transit authorities in some instances are considering service with self-propelled DMU cars, and in other instances are considering use of electric LRVs that do not comply with the safety standards of FRA. The principal drawback to these strategies from the point of view of the FRA is that those vehicles lack the physical strength to provide crashworthiness should they collide with conventional railroad equipment that would be sharing the same tracks. 

A survey of the existing and planned operations has been conducted and a system safety evaluation is being conducted to determine if possible equivalent safety of those equipment can be found. (see also System Safety)

Equipment Crashworthiness Research Publications and Papers

http://www.volpe.dot.gov/sdd/pubs-crash.html