Why Trains Crash Into Walls: The Physics of End-of-Track Protection
Stopping the Unstoppable: When an unstoppable force meets a dashpot snubber
In 2016, two commuter trains crashed into terminal walls because the engineers fell asleep. This article explains why end-of-track protection is a deceptively complex engineering problem. It breaks down the physics of stopping a train, from kinetic energy to deceleration, and compares solutions: static bumping posts, sliding friction stops, hydraulic dashpot snubbers, and even earth mounds. Using a garage model with an accelerometer, the author demonstrates how each device handles energy and why passenger safety demands a balance between stopping distance and force.
No matter how good the brakes are and no matter how experienced and well-trained the crew is, any system that depends on an individual, biological, fallible human, is eventually going to fail.
- glkindlmann
I am grateful that he put an accelerometer on the test train, and plotted the results: it was very cool to see effect of the dashpot snubber.
Also, the video introduced me to the term "dashpot snubber", but now when I try to learn more seems like dashpots and snubbers are distinct mechanisms [1]? I guess he demoed a snubber?
- Suhinnall27
I never realized how complicated safety devices had to be, and the dashpot snubber makes a lot of sense. However, why don't most trains the combination of the hydraulics and sliding stops as safety mechanisms? Is it because of the maintenance costs or the other external factors like the rust he discussed or the limit to the stopping space?
- ninalanyon
Were there no dead man's handles on those trains? Or do they have them and the drivers fall asleep frequently and most were caught in time but these two fell asleep at the latest possible moment?