From Railway Inertia to the Block System: Essay on the origins of railway operational safety

Abstract

What used to happen when a train experienced technical failure? Could the following train stop before reaching it? How were accidents avoided? These questions are central to the essay exploring the transition from railroad inertia to the blocking system.  

The application of the blocking system began with communication devices used between operators of two stations, where the permission to circulate in the section was guaranteed only when the track was free, avoiding the frontal encounter between trains or one train catching up with astractnother. Over the years, this system became "railway signaling" and in an evolutionary path reached the form of "automatic system of protection in the circulation". Today, it is possible to read the speed of a train and evaluate the running characteristics of the approaching train, in order to automatically apply the brakes or limit its speed to prevent the two trains from overtaking each other on the same track.