There were a lot of folks who finally passed the test, but who still never really got the any of the math and physics about how the brakes actually worked, And, there are a lot of things you can "get away with" for a while in life, until your luck runs out....and the "laws" of physics kick in.

We once had an incident on the SP where someone lost control with a train on the old main in the links at ten miles per hour and put the engines all over the ground on Spring Street. This individual had just been promoted about six months before. But, on hearing his explanation at the investigation, it became embarrassingly clear that he had no real idea how the air brakes actually worked. This resulted in much improved training.

The UTU griever actually got this individual off, with only a 90 day suspension, and an agreement that he would be restricted only to yard jobs when he returned to service. Which he did, until, a couple of years later, when the FBI showed up one day at the Shops, because it turned out that he was holding up banks, when he went out to beans.....

Physics, it's not just a theory, it's the "law"..........