A hundred years ago, Popular Mechanics, December 1915, carried a description of this invention to save the lives of the engineer and fireman of a locomotive that finds itself about to be involved in a head-on collision. Heretofore, the only options had been to either stay with the train or attempt to jump clear, and hope for the best. Even though the magazine admitted that there might be some practical problems, it was enough to give the men a fighting chance.
With a few seconds warning, the men could pull a lever on their seat. This would drop them, seat and all, into this thick cylinder, which would close itself and throw it free of the train. It was strong enough that it would hold even if the locomotive landed on top. And if it landed in the water, it would float.
Simultaneously, the lever would pull back the throttle, dump the fire, apply the brakes, and put sand on the tracks, so the departing engineer would be doing all he could for his passengers as well.