Friday, July 24, 2009

Real trains don't do rear end collisions

Real trains? Those are the trains with a real engineer, not a microprocessor, running the train.
The first unreal train was Bay Area Rapid Transit (BART) out in San Francisco. Originally designed for fully automatic, hands off, no engineer running, to save on California labor costs. Half way thru the project a design review showed the automatic control system was downright dangerous. The central computer (a Data General Eclipse if memory serves) would order a train to close doors and accelerate out of the station. The computer assumed that the trains did as ordered, and so, if it had ordered train 1 to depart the station, it assumed the station was clear and ran train 2 right into it. At the design review it was pointed out that should train 1 suffer anyone of a myriad of ordinary faults (blown fuse, broken wire, loose connector, etc,etc,ad nauseum) it would fail to depart the station as ordered, and the computer would ram the next train right into the back of it.
The project was too far along to redesign the cars and add a real engineer's position. They gave the poor engineer a windshield to look out of, and a big red panic button to slam on the brakes. Nothing more. The engineers rode along with the central computer running the train, and the engineer sitting in the front waiting for a catastrophe that required him to hit the panic button.
Couple months after opening, a BART train drove right off the tracks. It was the end of the line, and instead of heading back, the train drove forward off the end of line. It plowed thru a huge sand pile left as a bumper and wound up looking foolish. Thankfully, no one was hurt.
They asked the engineer why he had failed to hit the panic button before the train ran off the tracks. The answer went something like this. "I've been sitting in the front of that stupid train for 8 hours doing nothing. I must have not been paying attention, and we were off the tracks before I could do anything about it."
Lesson learned. Until the guy sitting in the front of the train is actually running the train, throttle, brakes, open and close doors, whistle for the grade crossings, watch the block signals and don't go thru a red signal, he will doze off, text message, read a book, anything to relieve the boredom, he isn't going to be alert enough to do any good when the automation breaks down.
Better not to have automation. Have the engineer actually run the train. You gotta pay him just to sit there, might as well have him operate the train. Save money, omit the automation.

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