Quote:
Originally Posted by Marshal
What are 'pressure plate systems'?
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Expo Line uses pressure plates, basically metal trampolines to detect when someone has stepped into the guideway at stations.
If something disturbs one of the pressure plates (such as a person or soda bottle falling onto the tracks) it emergency stops the trains.
Watching SkyTrain attendants test the plates is fun to watch, because they literally jump on each one like a trampoline.
The Millennium and Canada lines use a newer laser-based intrusion detection system, though it's not perfect either. While it doesn't have the same issues as the pressure plates, occasionally you get a newspaper or leaf blocking the laser and causing the trains to stop.