In this accident, the object that most likely punctured the locomotive fuel tank was a railcar coupler. The force required for a coupler to puncture a fuel tank is less than 1,000,000 pounds. For a coupler to penetrate a typical spent fuel cask used for rail transportation, a force of about 8,000,000 pounds would be necessary.

Because of the way that a coupler is attached to a rail car, it is impossible for a puncture force of this magnitude to be generated. The peak force associated with the regulatory puncture test on a spent fuel cask is usually about 2,000,000 pounds.

The cross-sectional area of a railroad coupler is about 364 square inches. This is much larger than the 28 square-inch cross-section of the regulatory puncture probe. The larger cross-section of the rail coupler means that it requires a larger force to puncture an object than the regulatory puncture probe (it would only require about 300,000 pounds of force for the puncture probe to penetrate the locomotive fuel tank).