BR(S) Posted June 1, 2014 Share Posted June 1, 2014 On May 30th, 66057 derailed at Doncaster station on a set of trap points: https://flic.kr/p/nw9HBv Discussion is on-going at http://www.railforums.co.uk/showthread.php?p=1809215#post1809215 and one contributor (entry #21) has stated that ". . . the AWS magnet is beyond the signal." [my emphasis]. My questions are is this AWS magnet positioning the case, if so then why and at which other locations does this happen? Link to post Share on other sites More sharing options...
Rugd1022 Posted June 1, 2014 Share Posted June 1, 2014 It does happen where there may be insufficient room for the magnet on the approach side of a signal, certain station areas around the country are like this. It also means a driver doesn't have to worry about stopping right on top of the magnet as this would require isolation of the AWS on the loco, contacting the signaller etc.... it can be a right old palarva at times. We had one at Rugby beyond (the now removed) RY63 signal on the Up Slow before the area was remodelled. Link to post Share on other sites More sharing options...
BR(S) Posted June 1, 2014 Author Share Posted June 1, 2014 I've managed to find a picture on Flickr of this AWS set-up. The text explains why the AWS magnet is where it is: https://flic.kr/p/4ZiU9V Link to post Share on other sites More sharing options...
Grovenor Posted June 1, 2014 Share Posted June 1, 2014 The text explains why the AWS magnet is where it is: But is a rather different scenario from the Doncaster freight line involved in this derailment. Keith Link to post Share on other sites More sharing options...
RMweb Gold TheSignalEngineer Posted June 1, 2014 RMweb Gold Share Posted June 1, 2014 Placing the AWS magnet beyond the signal was quite common at the exit to Goods Loops and other lines where trains normally stop at the signal. The normal position approaching the signal is not of much use at places where trains are regularly held or crew changes take place. Link to post Share on other sites More sharing options...
caradoc Posted June 2, 2014 Share Posted June 2, 2014 I'm struggling to understand this...AWS is an aid to Drivers in reacting correctly to approaching signal aspects. What would be the point of placing the magnet beyond the signal ? By the time the train passes over it, it may well already be too late to avert an incident. Link to post Share on other sites More sharing options...
BR(S) Posted June 2, 2014 Author Share Posted June 2, 2014 I'm struggling to understand this...AWS is an aid to Drivers in reacting correctly to approaching signal aspects. What would be the point of placing the magnet beyond the signal ? By the time the train passes over it, it may well already be too late to avert an incident. I think the problem arises (at least it did with me!) because we're used to thinking of the AWS magnet as a pre-signal warning device, with TPWS and trap points providing protection against a passed-signal incident. In the locations above (Doncaster and Bearsden), there is obviously a need to provide extra protection against a passed-signal incident, where a pre-signal AWS magnet would be of limited use (e.g. a crew changeover place). Presumably, where an AWS magnet is not positioned in a similar situation, a risk assessment indicates that TPWS or trap points are sufficient (e.g. at a station where a train terminates and goes out in the opposite direction but with the normal flow of traffic, such as those Thameslink services that terminate in platform 2 at Kent House). A further question might be would you ever see a post-signal AWS magnet without TPWS or trap points? I'm guessing the answer to this is no, with an AWS magnet being an additional form of protection to these. Link to post Share on other sites More sharing options...
BR(S) Posted June 2, 2014 Author Share Posted June 2, 2014 One other question about this placement of AWS magnets, with a view to modelling it: does anyone know when the practice started? I'm hoping it was in use in the 1986-1994 period. Link to post Share on other sites More sharing options...
RMweb Gold TheSignalEngineer Posted June 2, 2014 RMweb Gold Share Posted June 2, 2014 One other question about this placement of AWS magnets, with a view to modelling it: does anyone know when the practice started? I'm hoping it was in use in the 1986-1994 period. IIRC providing AWS beyond the signal would have started sometime in the 1970s. Originally it was in Standard Signalling Principle 43. The current standard is http://www.rgsonline.co.uk/Railway_Group_Standards/Control%20Command%20and%20Signalling/Railway%20Group%20Standards/GERT8075%20Iss%201.pdf. See part 2, particularly 2.1 6 - 2.1.9 for lines where AWS is to be provided and how it is to be positioned relative to signals. Link to post Share on other sites More sharing options...
kenw Posted August 21, 2014 Share Posted August 21, 2014 I'm struggling to understand this...AWS is an aid to Drivers in reacting correctly to approaching signal aspects. What would be the point of placing the magnet beyond the signal ? By the time the train passes over it, it may well already be too late to avert an incident. AWS was designed principally as an aid to reacting correctly to a signal at caution, by the time you're approaching a signal at Danger it's generally already too late if not reacting correctly. Even at the standard distance it's only 200 yards before the signal. Remember, this is a system dating from the 50s on a largely semaphore signaled railway, where it'd be provided at the distant signal, and not at stop signals, I think the problem arises (at least it did with me!) because we're used to thinking of the AWS magnet as a pre-signal warning device, with TPWS and trap points providing protection against a passed-signal incident. In the locations above (Doncaster and Bearsden), there is obviously a need to provide extra protection against a passed-signal incident, where a pre-signal AWS magnet would be of limited use (e.g. a crew changeover place). No, the AWS installation here will date from the 1970s resignalling. TPWS is a modern (post Ladbrooke Grove) add-on that's provided as additional protection. When positioned as shown, adjacent to the signal, the TPWS is a Train Stop Loop giving an immediate brake application, without warning, in event of the signal being passed at danger, By time it reaches the AWS magnet the brakes are already applied. It is possible though, that the AWS has been moved from adjacent to ahead of the signal to make way for TPWS. In many cases, on goods lines, loops etc, where trains are normally brought to a stand, AWS was not normally provided. Where it is, such as here, it's positioned at the signal to give a departing train indication, with the visual reminder as well as audible, of the state of the next signal ahead, thus performing it's original purpose. Once clear of the loop. the 'sunflower' if yellow / black's a reminder the next signal may still be at danger. Another factor with goods lines etc is these are usually 'Permissive Block' (ie allowing more than one train in section) making the normal AWS positioning 200 yards before the signal potentially hazardous.... A train, having had the 'calling on' at the previous signal's approaching the signal and expecting it may be at Danger... due to fog he still can't see it when the AWS bell (clear indication) sounds.... what he also still can't see's the light engine standing at the signal that it's just cleared for... Hope this clarifies some of the reasoning behind such positioning. Ken Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted August 21, 2014 RMweb Gold Share Posted August 21, 2014 Nor sure why I missed this one earlier (probably on my hols, again!). The situation is really very simple - AWS is only an aid, the thing the Driver should be giving his attention to is the aspect displayed by the signal (hardly a badly sited one in this instance). And if nothing else one might have hoped that a wide-to-gauge trap point standing open would also be noticeable unless he was starting away from a position tight up against it/the signal. However for all we know it could have been a SPAD due to a brake defect or poor rail conditions - and in neither of those cases would AWS have had the slightest unfluence Link to post Share on other sites More sharing options...
RMweb Premium Mallard60022 Posted August 22, 2014 RMweb Premium Share Posted August 22, 2014 Did anyone mention that the whole loop 'involved' in this 'incident' has been locked OOU since the derailment? P Link to post Share on other sites More sharing options...
kenw Posted August 25, 2014 Share Posted August 25, 2014 The situation is really very simple - AWS is only an aid, the thing the Driver should be giving his attention to is the aspect displayed by the signal Definitely! Although the original question related to why the AWS magnet's positioned as it is. (hardly a badly sited one in this instance). Not quite all it seems here, remember the photo's side on from some distance off (appears to be from shopping center car park). That signal's approached round a curve, and it's the center of three parallel running lines all with staggered signal positions, there's also a signal on the end of the through platform (no.8 ) that applies to the bay on the opposite side (no.7), while platform 8 signal's also on a gantry, towards the goods line. The classic miss-read trap (though don't know if and not saying that's actually the case here) Just been looking at the 'railforum' discussion quoted in the original question, also several posts there relating the signal being particularly badly sighted and, in fact, a multi-spad "well known to N,R.". Did anyone mention that the whole loop 'involved' in this 'incident' has been locked OOU since the derailment? Interesting point. The above points could have some bearing here. (edited to prevent a platform number appearing as an emotion) Link to post Share on other sites More sharing options...
DY444 Posted August 28, 2014 Share Posted August 28, 2014 The starting signals at Waterloo were provided with AWS inductors immediately after the signal as a means of alerting a driver to a SPAD in the days before TPWS was conceived. Some of these have been replaced by TPWS now but a number are still there. Other signals in the Wimbledon ASC area were provided with these too and most of them are still there - the Down Slow starter at Wimbledon is one I can think of . Link to post Share on other sites More sharing options...
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