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Reaction time
Author: Mike Stimpson
Date: 06-26-2009 - 09:20
No, there's reaction time issues. First, the operator sees it. Then he questions "Am I really seeing that?" and confirms, "Uh oh, there really is a train there!" Then he hits the brakes. Then there's a lag time for the brakes to apply.
All of the above could easily be two seconds. How fast was the train moving? 50 miles an hour? That's 73 feet per second. Two seconds gives 146 feet in reaction time. That plus the 125 feet of braking add up to 271 feet of sight line.
Note well: the above numbers are back-of-the-envelope numbers, despite the misleading precision. My point is that the reaction time - both human and mechanical - could easily eat up a lot of distance.
All of the above could easily be two seconds. How fast was the train moving? 50 miles an hour? That's 73 feet per second. Two seconds gives 146 feet in reaction time. That plus the 125 feet of braking add up to 271 feet of sight line.
Note well: the above numbers are back-of-the-envelope numbers, despite the misleading precision. My point is that the reaction time - both human and mechanical - could easily eat up a lot of distance.
