Yes, can't see how it'd be considered otherwise as that's the sole purpose of the flashing green aspect, isn't it?
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Flashing green aspects
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HSTEd
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How would these be handled by AWS?
Would a steady green be reported by a restrictive aspect by the AWS? Since it can't know what sort of train is approaching.
Would a steady green be reported by a restrictive aspect by the AWS? Since it can't know what sort of train is approaching.
Railsigns
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Steady green and flashing green aspects are both accompanied by a 'clear' AWS indication (bell). See bottom of this page.
That's actually why I started the thread - I was able to hear the bell while on a Scotrail 170 and thoughts started wandering.
You get an AWS horn for single yellow, double yellow, flashing single and flashing double as well as a fixed distant, ESR, TSR, PSR and signals in the wrong direction. Having a bell for both green and flashing green doesn't feel like an issue.
Oh, I didn't think it would be an issue. I was just thinking about it - technically it's a restrictive aspect but you'd get a bell. Seemed interesting.
I don't believe the horn is exclusive to restrictive aspects. So for me Green = Bell. Everything else gets the horn. Getting a horn on a green would be confusing. I know places where getting a green means I'm putting in the brake.
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Railsigns
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The fundamental function of AWS is to check the alertness of the driver and, if necessary, enforce a brake application at or before the point where braking may need to commence. Hence, when AWS was applied to semaphore signals, only the distant signals were fitted, not the stop signals (except where these were combined with a distant signal). Two-aspect (red/green) colour light signals were often not fitted with AWS either.
A test train running at 140 mph under flashing green aspects needed to begin braking upon passing a steady green aspect; however, it wouldn't receive its first AWS warning until the next signal, which would be displaying double yellow (assuming it hadn't stepped up to a higher aspect while the train was approaching). In other words, the AWS is doing its job too late in this instance. This is one reason why flashing green aspects are no good for running trains at speeds above 125 mph in normal service.
A test train running at 140 mph under flashing green aspects needed to begin braking upon passing a steady green aspect; however, it wouldn't receive its first AWS warning until the next signal, which would be displaying double yellow (assuming it hadn't stepped up to a higher aspect while the train was approaching). In other words, the AWS is doing its job too late in this instance. This is one reason why flashing green aspects are no good for running trains at speeds above 125 mph in normal service.
If anyone is interested there is a video of the 140mph+ test runs in 1989 in the link below, which clearly shows the flashing green aspects.
https://www.youtube.com/watch?v=mYfq79jXI7A
https://www.youtube.com/watch?v=mYfq79jXI7A
Is it not the case that all stock cleared to run at 140mph (or previously cleared to) could brake from 140mph from the first double yellow to a standstill with a full (non-emergency) application, though with provisos about passenger comfort above?
Railsigns
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That sounds unlikely. If that were true, there would have been no point in providing the flashing greens and, since these were only installed for test trains, passenger comfort wasn't an issue.
On the latter, presumably as it indicates a wrong routing?
In some cases yes.
What I am concerned with when I'm running on green and at linespeed is that I still have to remember the next max permissible speed. Some green's will take you across on to a diverging route with a lower linespeed.
Signals aren't just about running through the sequence and we also have places where your deliberately slowed down and the point of conflict is given a extra section (G 2Y 1Y R R) and the Flashing yellow sequence will also extend your red to an extra section (2FY 1FY 1Y R)
When driving, route knowledge is very very important.
--- old post above --- --- new post below ---
and some signals don't have AWS....
edwin_m
Veteran Member
Were/are any special safety precautions required for 140mph test running? For example a second person in the cab observing signals to make up for the reduced sighting distance and lack of an AWS horn for a steady green, or do they even have to run under possession (in which case the signals could be irrelevant anyway!)?
Presumably the Azumas have been using the 140mph facility for acceptance testing, including 10% overspeed. Does this mean the braking distance is good for 154mph?
Presumably the Azumas have been using the 140mph facility for acceptance testing, including 10% overspeed. Does this mean the braking distance is good for 154mph?
turntablist
Member
wow best class 91 vids ive seen,
https://www.youtube.com/channel/UChV5h7_XtvPb9Xsb3GwiGjA
thanks to
avocet1989
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