That and actually not killing a great many people, as that dj light signal would inevitably do sooner or later. Rail signaling isn't just a convenience and thro

That and actually not killing a great many people, as that dj light signal would inevitably do sooner or later. Rail signaling isn't just a convenience and throughput optimization like road traffic lights are, with little consequence in the case of failure. Failing rail signals are more deadly than falling air traffic controls.