US: The Department of Transportation (USDOT) recommended all US cargo operators to bring the current fleet of tank cars intended for the transportation of Class 3 flammable liquids quicker to the safety standard DOT-117 (for new cars) or DOT-117R (for overhauled ones).
Under the FAST Act, adopted in 2015, the entire fleet of such tank cars must comply with DOT-117/DOT-117R standards by 2029. According to a report by the US Bureau of Transportation Statistics (BTS), 57% of all tank cars were brought to these standards in 2021. Currently, the Association of American Railroads (AAR) says it is necessary to replace more than 35,000 cars or about 8% of the fleet of all tank cars in North America (data from 2021).
Relevance of the replacement
The problem became acute against the derailment of a Norfolk Southern (NS) freight train with highly toxic chemicals near East Palestine (Ohio), which took place on 3 February. According to a preliminary report by the National Transportation Safety Board (NTSB), 38 cars derailed, including 11 tank cars carrying flammable liquids and fuel gas. The tanks lit up, causing a fire that damaged 12 more cars.
The bearing malfunction is considered to be an accident factor. It is noted that shortly before the crash, the train crew received an alert that the bearing temperature of one of the cars exceeded the ambient temperature by 122.7 °C. After receiving the signal, the driver turned on the emergency braking followed by the crash. According to NTSB, the bearing was about to fail due to overheating a few minutes before the derailment.
Another NS train crash occurred on 4 March. The operator says that 28 out of 212 train cars derailed near Springfield. The train was not carrying any dangerous chemicals. Subsequently, NS found unsecured wheel sets on a number of recently purchased rolled steel cars, which pose an increased risk of derailment on a differing track. AAR immediately issued an official notice ordering all operators to decommission such cars, inspect them and replace all wheel sets of this type.
There were also many other cases of train derailments of different operators in February-March in the US. However, this situation is typical for the country’s railway system. According to BTS, 54,539 derailments were recorded in the US for 1990-2021, an average of 1,704 per year. In 2022, trains derailed 1,164 times.
Reaction of the US authorities
The train crash on 3 February caused a wide public response. USDOT presented its recommendations on preventing such incidents two weeks later. Among the steps for cargo operators, recommended by the department, it is possible to highlight the quicker launching of tank cars that meet DOT-117 or DOT-117R safety standards, the deployment of new technologies for checking rolling stock and the adoption of regulatory documents requiring the presence of at least two people in the locomotive crew.
The agency also stated that it will continue to ensure the safety of rail transportation, including:
- initiating a safety inspection programme on routes where trains with a high risk of ignition run and a programme for checking tanks with a long service life, as well as cargo operators who have decided not to switch to DOT-117 tank cars,
- allocating funds for the overhaul of tracks, removal of at-grade crossings and improvement of safety within the framework of the approved large-scale five-year state plan for infrastructure investments totalling $1.2 trln,
- further developing of regulations for the introduction of electronically controlled pneumatic (ECP) brakes, which can potentially reduce the braking distance by 60% compared to conventional pneumatic ones.
It is worth noting that under the FAST law, every freight train consisting of 20 or more tank cars carrying Class 3 flammable liquids had to be fitted with ECP brakes. However, this requirement was cancelled in 2017 by the administration of US President Donald Trump due to the fact that “the expected costs of ECP brakes significantly exceeded the expected benefits”. Secretary of Transportation in the US Pete Buttigieg said the technology could have prevented the crash. However, according to NTSB Chair Jennifer Homendy, the train should not have used such a braking system, as it included only 3 tank cars carrying Class 3 flammable liquids.
Operator’s response measures
A few weeks after receiving the USDOT response, NS itself announced its own measures to improve security. First of all, the operator plans to install 200 additional fault detectors for bearings along the tracks and place 13 new acoustic fault detectors that analyse the acoustic characteristic of vibration inside the axle.
The operator also announced that it is working with manufacturers to accelerate testing and deployment of next-generation bearing fault detectors that can scan a larger cross-section of bearings and car wheels. The company will also speed up its digital train inspection program in collaboration with Georgia Tech Research Institute. It is aimed at diagnostics of rolling stock using computer vision and AI-based algorithms.
It is worth noting that NS, along with a number of other major operators, is a member of the RailPulse joint venture, which, with the support of USDOT, is currently engaged in a project to introduce on-board telemetric on freight cars, including for tracking the health of components. Early in February, the Principal of the Rail Supply Chain Associates, Robert Cantwell, called for moving to on-board diagnostic systems in the Railway Age magazine. According to his estimates, equipping one freight car with a telematic sensor that allows monitoring the condition of the car’s components can cost up to $1,000.
About the DOT-117 standard
This standard was developed in 2015 by Transport Canada and the US Federal Railroad Administration in response to the crash of a train with oil tank cars in 2013 in Canada. According to the specifications of the standard, the tank bodies should be made of 22.8 сm thick steel with 11 mm thick sheet metal casings, 1.2 cm thick head guards at the ends of the tanks and improved valves compared to previous designs. In general, such cars should be more resistant to impact and external effects of high temperatures. However, the standard does not provide for equipping rolling stock with ECP brakes.
Scheme of the DOT 117 tank car (enlarge). Source: wikipedia.org
According to the latest AAR data, more than 35,000 tank cars for the transportation of Class 3 flammable liquids do not meet the requirements of DOT-117. Matt Elcott, a stock market analyst at Cowen Inc., says that the combined production capacity for such tank cars from the largest manufacturers Greenbrier and Trinity Rail (more than 70% in this market branch) in 2024 will be more than 5,000 units.
A National Steel Car tank car compliant with the DOT-117 safety standard. Source: National Steel Car
A Greenbrier tank car compliant with the DOT-117 safety standard. Source: Greenbrier
At the same time, the rolling stock consistent with the DOT-117 standard is not represented in the portfolio on the Trinity Rail website. Greenbrier offers such tank cars most widely: there are six models in the company’s line with a tank volume from 96 to 115 m3. The portfolio of another manufacturer – National Steel Car, Canada – includes three models of such tank cars in approximately the same volume range.