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Old 5th July 2019, 12:27
Beeyar Wunby's Avatar
Beeyar Wunby Beeyar Wunby is offline  
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Join Date: Dec 2012
Location: NW Norfolk
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I've edited my original post, as I've had time to sit down and read the first half of the report. And it's scary stuff.

Driving at 80 mph over a route the driver clearly didn't have a clue about, in the dark, and rain? That's just crazy.

Could an overspeed accident like that happen here ? Well it could happen anywhere, but we do have 2 pieces of technology to try to prevent it.

Firstly, whenever there's a reduction in Permissible Speed of 33% or more it's a requirement that an AWS magnet and warning board are placed at Service Braking Distance from the start of the lower speed. The magnet does what it always does; it sounds a little horn in the cab telling you that you must acknowledge the warning by pressing the cancelling button, otherwise the Emergency Brake will be applied automatically. But what it really means is LOOK OUT OF THE WINDOW NOW, where of course you'll see the triangular warning board which tells you to START BRAKING, and the speed that you need to get down to.

Wiki article here...https://en.wikipedia.org/wiki/UK_rai...eed_indicators

Secondly we a have a speed trap on the approach to the lower speed. This is a TPWS Overspeed Sensor, which consists of a pair of radiating loops in the four foot, and a receiver and timer on board the train. The distance between the two loops determines the capture speed, such that if the train traverses both in less than ~0.9 seconds the system fires and the emergency brake is applied. And of course an Emergency Brake Application cannot be overridden. Once it fires, the train must come to a stand, and a penalty timeout occurs. Only after an elapsed time will the brakes release.

Wiki article here...https://en.wikipedia.org/wiki/Train_...Warning_System

These two systems are extremely good, but anything can malfunction, and it is possible to isolate them (although this is governed by strict rules and most train companies just won't run trains in this condition). But we all go around hoping that the damn things work when they're needed.

Cheers, BW.

Last edited by Beeyar Wunby; 6th July 2019 at 11:31.
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