AllTranstek tackles imploding tank car legend on MythBusters TV show

By Daniel Niepow, Associate Editor

In mid-January, the Discovery Channel aired an episode of MythBusters that featured the TV show's biggest logistical operation to date: an investigation into the legend of the imploding tank car.

The tank car imploded only after sustaining significant external damage.
Photo: AllTranstek LLC

The premise was that a tank car would collapse if its internal pressure fell significantly below outside air pressure. According to legend, the scenario played out for an unsuspecting locomotive engineer who steam-cleaned a car during a rainstorm. He stepped out and sealed the unit full of hot steam, which condensed and contracted from the rain. The resulting pressure differential supposedly caused the car to crumple.

The team behind the long-running popular science series had been hoping to tackle the myth for nearly a decade, says Dan Tapster, MythBusters' executive producer.

"We had numerous attempts but never really made much progress at all," he says. "For our final season, this was the sort of big story that we wanted to do, so we pulled out all the stops and decided to go for it."

One of the biggest hurdles the producers faced? Obtaining cars they could test. So, the MythBusters team got in touch with rail consulting firm AllTranstek LLC, which provided general guidance, two DOT-111 tank cars, and a site in Boardman, Ore., to carry out the experiment.

"They were exactly the kind of 'one-stop shop' that we needed for an experiment of this nature," says Tapster.

In the wake of several high-profile derailments involving the same DOT-111 cars shipping crude oil, AllTranstek’s leaders initially were hesitant about linking the company name with the experiment. After further consideration, they decided that participating in the show could actually be a positive thing for the company and the rail industry as a whole.

"It was a good technical experiment that we wanted to participate in," says Dave Ronzani, director of rail-car regulatory compliance at AllTranstek. "We were going to be able to bring some data to the industry."

Plus, the company could help the crew carry out the experiment safely.

"These guys were going to do it anyway, and we wanted to make sure they did it the right way and with the right supervision," adds Dick Kloster, senior vice president and chief commercial officer at AllTranstek.

The show, whose final season wrapped up earlier this month, typically takes on multiple myths in each episode. But this time, the producers slotted an entire episode to explore the imploding tank car myth.

During the episode, the show's hosts Jamie Hyneman and Adam Savage tested the myth's premise on increasingly larger objects, beginning with a one-gallon metal can and eventually moving on to a DOT-111 tank car. They sealed each one with steam and then allowed it to cool to initiate the implosion.

Each object crumpled except the tank car, which didn't budge even after being steam-cleaned and sprayed with cool water.

In an attempt to initiate an implosion, the MythBusters team first steam-cleaned the rail car (top photo) and then hosed it down with cool water (bottom photo).
Photos: AllTranstek LLC

"Everyone involved had told us repeatedly that the tank car would crush with the pressure differential we were dealing with," says MythBusters' Tapster. "So when it didn't we were all left scratching our heads."

The team rolled out a second tank car to try again, but it was to no avail. Finally, the MythBusters crew dropped a 3,200-pound concrete slab on the car, which created a six-inch dent on top of the unit. With its structural integrity compromised, the car imploded.

As a result, Hyneman and Savage declared the imploding tank car myth "busted." Absent significant damage, the cars will remain intact, even with the massive pressure differential.

Still, it's not "completely uncommon" for a tank car to implode, says AllTranstek's Ronzani, noting that this kind of incident could happen at a shipping facility if a car has been been mishandled or misused.

"We thought the car was going to implode a lot easier than it did," he says. "I think that it should give some level of satisfaction that the cars are tougher than maybe some people had expected."

After the show aired Jan. 16, the rail industry's response was positive, Ronzani says. Most folks that reached out to him found the episode interesting, with some asking a few specific technical questions about the experiment. Others asked how the company got involved and what it was like to participate in the show.

And as for meeting the MythBusters duo?

"It was a lot of fun," he says. "Both guys posed for pictures with us and autographed our hard hats."

The Discovery Channel's trailer for the imploding tank car episode.