THE Transportation Technology Centre located in Pueblo, Colorado, is the largest railway testing facility in the world with over 80km of test track. Operated by Ensco on behalf of the US Federal Railroad Administration (FRA), it provides a wide range of specialised services ranging from precision testing of new wagon designs to advanced training for emergency responders. By meeting the evolving needs of heavy haul railways, TTC is helping to ensure that the industry is prepared to meet emerging challenges.
For the type or homologation testing of new wagon designs, TTC facilities include a precision test track and a wheel-rail mechanisms track which have intentional track geometry perturbation to induce dynamic responses from the wagon. There is also a unique high-speed adjustable perturbation test track, as shown on below, a section of slab track that enables track geometry perturbations to be created in order to evaluate associated rolling stock performance.
Type testing involves testing at all speeds to ensure safe operation, measuring wheel forces through the use of instrumented wheelsets. Vehicle dynamics service worthiness testing includes harmonic scenarios such as pitch and bounce, yaw and sway, and twist and roll. One of the most challenging tests focused on identifying wheel climb risk is dynamic curving, where wagons encounter several track geometry perturbations located on a curve.
A key element of performing these tests at TTC is that they do not interfere with revenue railway operations. Track geometry perturbations are precisely created and controlled during testing to ensure consistency. Vehicle dynamics testing at TTC is compliant with Association of American Railroads (AAR) standards, but track geometry perturbations can be precisely adjusted and validated with a track geometry measurement system in order to replicate conditions worldwide.
TTC also has full-scale laboratory facilities for testing new wagon designs. The rail dynamics laboratory is equipped with several testing rigs, such as the squeeze test fixture that applies a 11.6MN compressive load to the vehicle to assess crush strength, which is associated with crashworthiness. The Simuloader has 13 servo-hydraulic actuators that apply loads directly to the vehicle frame. With a maximum load of 3.34MN, the Simuloader can replicate a lifetime of fatigue loads from revenue service in a fraction of the time. The vibration test unit is a whole-vehicle vibration test rig, which applies vibrational loads of between 0.3 and 30Hz at the wheelsets which induce full bogie suspension, carbody and load vibration.
A key element of performing these tests at TTC is that they do not interfere with revenue railway operations.
TTC is also unique in its ability to perform full-scale crash testing of rolling stock, which is required for tank cars to ensure that hazardous materials are not released during a derailment. Crash testing is conducted using TTC’s impact wall, a fortified concrete structure able to withstand 13.4MN of impact force. During impact testing, a tank car is placed adjacent to the wall where it acts as an immovable reaction structure. A separate ram car is used to simulate a derailed freight wagon’s coupler piercing the tank car shell.
High-speed cameras and sensors capture detailed data on the deformation, energy absorption and overall structural performance of the vehicle during impact. This data is often used to validate non-linear Finite Element Analysis (FEA) simulation models of new rolling stock, and testing at TTC has helped to develop new tank car standards including the latest DOT-117 specification in North America which has produced a significant improvement in performance when compared with the earlier DOT-111 design.
TTC also undertakes crash testing of locomotive fuel tanks and fuel tenders, which is becoming increasingly important with the emergence of alternative fuels such as hydrogen and renewable natural gas (RNG) or biomethane. Testing includes the simulation of a derailment that causes the weight of the locomotive be borne by its underfloor-mounted fuel tank, and a broken rail piercing the fuel tank. Other key impact scenarios are coupling at a higher speed than is recommended, longitudinal deceleration events within the train, and the impact from a highway vehicle striking the side of the locomotive at a level crossing.
Fire and hazardous materials
Fire safety is also of key importance to tank cars carrying hazardous materials and locomotives running on alternative fuels. TTC’s fire testing capabilities are designed to evaluate how these vehicles perform in the event of a fire, ensuring that they meet the highest safety standards. TTC has all the required regulatory permission to conduct fire testing within its 13,000ha site and has its own dedicated fire-fighting capability.
Fire testing of tank cars involves subjecting the vehicles to controlled burn scenarios, where the car is engulfed in flames to simulate real-world conditions. The tests focus on evaluating the performance of safety features such as thermal protection systems, pressure relief devices, and the structural integrity of the car under high-temperature conditions. Given the potentially catastrophic consequences of a fire involving hazardous materials, these tests provide critical insights into how tank cars behave in extreme situations and what improvements can be made to enhance safety. For alternative fuel locomotives, fire testing is particularly important due to the unique properties of the fuels involved. RNG and hydrogen present their own set of safety challenges, including the risk of fire and explosion.
Another unique facility at TTC is the Facility for Underground Rail Security and Safety Testing (FURRST). Funded by the US Transportation Security Administration (TSA), this is designed to address critical security and safety concerns within the industry, such as train fires taking place in a tunnel, enabling smoke and fire conditions to be evaluated in a confined tunnel space.
Fire testing enables engineers to understand how fuel containment systems, insulation and other safety mechanisms and controls perform when exposed to fire. This data is crucial for developing robust safety protocols for alternative fuel locomotives, ensuring that they can operate safely even in the event of a fire-related incident.
The Ambipar Response Training Centre (ARTC) located at TTC enables first responders to experience real-world freight train accident scenarios. Within simulated railway environments that include real tank cars in mock derailments and simulated releases of liquids and gases, first responders learn how to handle incidents involving hazardous materials, lithium-ion batteries and hydrogen. The training team provides expert knowledge of the latest techniques and tools to manage such emergencies effectively.
Students are also exposed to live fires in order to gain crucial hands-on experience of tackling such incidents, and to develop their understanding of the behaviour of fires involving hazardous materials, lithium-ion batteries and hydrogen in a railway context. ARTC offers courses that can be customised to meet the specific requirements of different operators and emergency responders, and works closely with industry leaders and researchers to stay abreast of the latest developments in railway technology and emergency response strategies.
The Second Annual TTC Conference and Tour takes place on October 22-23 and enables organisations at work here to share the fruits of their research with the wider railway community.
*Matthew Dick is vice-president of strategy and business development at Ensco, which has operated TTC since October 1 2022 under a contract awarded by the US Federal Railroad Administration (FRA).
