During World War 2 the United States Office of Strategic Services & National Defence Research Committee performed a number of tests to determine the most effective way to disrupt enemy railroad services. The "Mole" was an explosive device designed to automatically detonate when light levels dropped, such as when a train entered a tunnel. This film shows how the Mole was made, as well as various tests to determine the most effective location to place the Mole. Needless to say there's quite a few trains being blown up, derailed, or otherwise wrecked in this movie! .

In March 1944 the United States National Defense Resources Committee & Office of Strategic Services performed a number of experiments on the Claiborne-Polk military railroad to help determine the best way to derail trains. The results were presented in the film "Derailment".

The film discusses amount of explosive used, technique of making "gaps" in railroad track to overturn train. Uses filmographic techniques such as slow motion, reverse motion, and freeze frame to show effects of "gaps" and explosives on train and results of experiments. Illustrated arrows point to areas of train considered especially relevant to experiment. Narrator explains each type of explosive and reason for variations. Great archive footage of the old steam trains.