What happens when you crash-test a tank car

Trains News Wire takes you to the first-ever real-world test of a DOT-117 tank car
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Kathi L. Kube
The DOT-117 tank car is in position against the impact wall at the Transportation Technology Center. The trucks have been removed and the car is supported on skids. Above the car is a high-speed camera, which researchers will use to evaluate subtle details during the impact. The markers and grid in the target area will assist them in taking measurements.
PUEBLO, Colo. – A new tank car’s crash test results may be just months away. Though information government researchers gathered on a DOT 117-type tank car impact test in September will take time to analyze, Federal Railroad Administration officials say they’ll post early results by the end of the year on their website. Trains was the only media outlet on site at the Transportation Technology Center near Pueblo, Colo., for the test, which researchers say will help them validate computer models and develop new performance standards for future tank cars. DOT 117 cars are meant to replace older-design DOT 111 cars in high-hazard flammable liquids service.

In May 2015, the FRA and the Pipeline and Hazardous Materials Safety Administration jointly released a final rule for tank car standards and operations controls. On Sept. 28, the FRA put the new car design through its paces with a side impact test at the research center.

“Previous tests on the DOT 111 and 112 cars provided information for the design of the regulations,” says Francisco González III, tank car and hazardous materials project manager with FRA. “Today we’re going to get information on how the DOT 117 tank car performs and put that back into the model.”

FRA tasked representatives from the John A. Volpe National Transportation Systems Center of Cambridge, Mass., with modeling and analysis.

In preparation for the test, TTC personnel had removed the car’s trucks and mounted it on a support nearly flush to the facility’s impact wall. One of TTC’s test locomotives, AAR 2000 (a GP40-3) was coupled to a flatcar modified into an impact car with a 12 by 12-inch ram.

At the appointed time, the impact car accelerated downgrade to the target 13.5 mph and rammed the impactor into the broad side of the tank car, which was fitted with a wide array of sensors.

The impactor hit the car, sounding like a cross between cars coupling hard and an auto crash. As expected, the roundness of the cylindrical car morphed into an oval as the impactor pushed into the car, which itself was pushed backward into the wall then rebounded pushing the impactor back toward its origin.

Despite being on a downgrade, the impact car did not roll back toward the tank car again because its air hose had been extended with a PVC pipe. A fraction of a second before the impactor hit the tank car, a large piece of metal installed between the rails broke the pipe, activating the impact car’s brakes.

Dust rose from beneath the car as it resumed a near-cylindrical shape, albeit with a large dent.

Prior to the test, the car was filled with water with a 5 percent outage. Immediately following the test, TTC personnel approached carefully to be certain the tank had not breached and retrieved their high-speed cameras. After they ascertained the site was safe, observers were permitted to return to the car for a closer look.
TankCarGlossaryNEW
Tank Car glossary
Association of American Railroads/Kathi L. Kube
The DOT 117 standard specifies that the tank car’s shell must be 9/16-inches thick, right between earlier 111 and 112 models. The jacket was clearly deformed and, in the immediate area of the impact, broken.
 
After sufficient time to look at the damage to the jacket, researchers and observers returned to a conference room for a debriefing while TTC personnel removed the car’s jacket and thermal protection for a better look at the tank itself.

“The crash-worthiness range for this test, according to analysis performed by Volpe, was between 13 and 14 mph,” says González. Therefore, FRA decided to run the test at 13.5 mph. “The actual speed was 13.6, according to preliminary analysis. … The impact deformed the car but did not puncture it, so it agreed pretty well with the model.”

Once the jacket was removed, we returned to the impact wall. The jacket, now removed, laid on the ground, clearly deformed. While the dent to the tank was clearly deep, its integrity was intact.
 
Post-test, the tank car rested several inches from the impact wall. It also had noticeable dents to the back, although not nearly as deep as the point of impact. There was also evidence that the car slid significantly on the skids upon which it rested.

The dust that arose from the car following impact came from a concrete slab beneath the car. It appears that as the car ovalized, or as the cylindrical shape was squished into an oval shape, the bottom outlet valve’s skid protection rammed into and scraped along the slab. Prior to the test, the skid protection had a few inches’ clearance; post-test, it rested in rubble.

Researchers plan to take small samples, or coupons, of the shell to send for metallurgical analysis. Final results will be available in several months, and researchers at that time will decide if they need to do additional tests on the DOT 117.
 
However, some results will be published on FRA’s website by year’s end.

UPDATE: Clarification in glossary terms. Oct. 18, 2016, 11:04 a.m. Central time.

NEWSWIRETrains News Wire

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