w.r.t. the Scottish incident...
Quote:
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Originally Posted by The BBC said
The RAIB said neither of the train drivers was aware of the emergency speed restriction at the time they drove their trains over the affected section of track.
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This is odd. The whole point of an
EMERGENCY speed restriction is that a driver is not expecting to see it. They can be imposed without any warning,
and if set up properly are almost impossible to miss. But they can be set up incorrectly by track workers who haven't been instructed properly.
The sequence approaching an ESR consists of ;
1) A yellow Emergency Indicator board with 2 bright flashing white LED lamps. Hard to miss this BUT, if you weren't looking out the window it wouldn't matter because there's an AWS magnet immediately after it. It will activate the AWS horn in the cab...and if you don't respond to that the Emergency Brake will operate, and you'll be stopped.
2) Shortly after that there's a yellow Warning Board showing the speed in black numbers with 2 retroreflective white circles below it. This is also followed by an AWS magnet, which again you must cancel or it will put the Brake on.
So far then, the driver has been presented with 2 warning boards and 2 AWS magnets they've had to cancel - in a place where there aren't normally any.
HOW THE HELL COULD A DRIVER MISS THIS? (That's a rhetorical question, because it happens
)
At this point the driver needs to apply the brake and get hold of the train.This does not require a 'Casey Jones spark shower episode'. Modern trains with disc brakes need only apply a reasonable, steady force to bring the speed down smoothly.
3) So after the train has travelled the allotted Service Braking Distance - which would be over a mile in length to bring a train down from 100mph to 20mph (there are charts and tables to tell the people setting up the ESR how long the approach to the start of the Restriction should be from the Warning Indicator) there will be a yellow Commencement Board. This will display the speed of the restriction in black letters on a yellow board - in this case 20.
And at the end of the ESR will be yellow Termination Board. Once the last vehicle of the train is clear of the T the driver can accelerate away.
If you want to see what these look like, I wrote this Wikipedia section some time ago.....
BW's Speed Restrictions
As ever, we await further details of this incident with bated breath.
BW