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| Approach locking 28/03/2015 at 17:26 #70449 | |
belly buster
368 posts |
Quick question. I cancelled signal 81 (Wichnor Jn) as it was set to Auto and I had to get a train out of Barton Rivers. It gave me a 180 approach locking even though the approaching train was still passing signal 1 with 2 greens ahead. Is this correct behaviour? 
Post has attachments. Log in to view them. Last edited: 28/03/2015 at 17:29 by belly buster Log in to reply |
| Approach locking 28/03/2015 at 17:39 #70452 | |
welshdragon
315 posts |
Yes, it is a long time-out, don't ask me why though!
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| Approach locking 28/03/2015 at 17:54 #70453 | |
KymriskaDraken
963 posts |
Maybe they didn't think about having comprehensive locking there. Kev Log in to reply The following user said thank you: belly buster |
| Approach locking 28/03/2015 at 18:11 #70455 | |
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AndyG
1834 posts |
Same as some signals on Trent, basically a cost saving measure, it can take quite a few relays to set up comprehensive Approach locking.
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply The following user said thank you: belly buster |
| Approach locking 28/03/2015 at 18:21 #70457 | |
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Hpotter
205 posts |
Correct, Non-comprehensive interlocking here, so time to be wary of possible trains from Muddy Waters, aka Barton RCMD.
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| Approach locking 28/03/2015 at 23:55 #70480 | |
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belly buster
368 posts |
Just tested it, you get 180 seconds approach locking even if there is nothing approaching at all. Same with signal 79. Probably best to leave the autos switched off on these two.
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| Approach locking 04/04/2015 at 21:26 #70766 | |
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Slash
76 posts |
One signal gives you 240 Seconds. Speaking to S&T the other day, the Guildford area is all 240 seconds and non-comprehensive, madness! Log in to reply |
| Approach locking 04/04/2015 at 21:38 #70768 | |
jc92
3629 posts |
" said:Same as some signals on Trent, basically a cost saving measure, it can take quite a few relays to set up comprehensive Approach locking.same on Cowlairs. they can be quite painful at 240 secs each. IIRC Aldwarke Jct interlocking also consists totally of 240sec non comprehensive locking. "We don't stop camborne wednesdays" Log in to reply |
| Approach locking 04/04/2015 at 21:42 #70769 | |
BarryM
2158 posts |
" said:One signal gives you 240 Seconds."madness" ? No! Safety reasons with this type of interlocking. Look both ways before you press that button or stroke that lever! Barry Barry, Sydney, New South Wales, Australia Log in to reply |
| Approach locking 04/04/2015 at 21:43 #70770 | |
headshot119
4869 posts |
" said:" said:A few 240, and a few 180 non comprehensives on Llandudno Junction. Quite painful if you clear LJ57 and change your mind!Same as some signals on Trent, basically a cost saving measure, it can take quite a few relays to set up comprehensive Approach locking.same on Cowlairs. they can be quite painful at 240 secs each. IIRC Aldwarke Jct interlocking also consists totally of 240sec non comprehensive locking. " said: " said:It is a safety feature, but at the same time it's only like that as a cost saving measure.One signal gives you 240 Seconds."madness" ? No! Safety reasons with this type of interlocking. Look both ways before you press that button or stroke that lever! "Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Last edited: 04/04/2015 at 21:45 by headshot119 Log in to reply |
| Approach locking 04/04/2015 at 22:01 #70773 | |
Steamer
3920 posts 
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Out of interest, why are some areas 120 seconds, some 180 and others 240?
"Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Approach locking 04/04/2015 at 22:27 #70775 | |
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Stephen Fulcher
2022 posts |
It's all calculated at the design stage on a per signal basis. http://www.rgsonline.co.uk/Railway_Group_Standards/Control%20Command%20and%20Signalling/Railway%20Group%20Standards/GKRT0063%20Iss%201.pdf is worth reading to give you an idea. It's worth noting that this has nothing to do with whether it is comprehensive or not, just the time. Whether to provide comprehensive approach locking is another decision based on cost and the likelihood of needing to replace a signal without a train having passed. When I get home I'll pick on a random example from SimSig and draw up an idea of the approach locking circuits to show you what I mean by that. Edit: I also suspect there will be a lot more yuan just the two signals mentioned here on Derby panel that will have either different times or be non-comprehensive. Last edited: 04/04/2015 at 22:29 by Stephen Fulcher Log in to reply The following users said thank you: flabberdacks, Steamer |
| Approach locking 05/04/2015 at 08:10 #70783 | |
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Sparky
84 posts |
Speaking from professional experience cost being a factor in determining the timing of approach locking is bogus. The equipment cost required for the different times is the same. In relay/route based systems the timing is provided by a QTD5 'Q' type relay and this relay has the ability to be set at any time period from 2.5 sec - 325 sec. In CBI (microlok, SSI, Westlok etc)systems changing the timing is as simple as changing the figure is the timer configuration. In 95% of cases the approach locking timing is determined by local conditions. Line speed of the fastest train to travel that section, weight of heaviest train, gradient of track, sighting distance to name but a few factors. People have to remember that the timing of any safety system is always set up to cover the worst case scenario fastest, heaviest train in the worst visibility etc. I intend to live forever. So far so good Log in to reply |
| Approach locking 05/04/2015 at 09:01 #70784 | |
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Danny252
1461 posts |
" said:Speaking from professional experience cost being a factor in determining the timing of approach locking is bogus....has anyone said that it was a factor? I've not seen any claim that shorter/longer locking times are any different in price. Log in to reply |
| Approach locking 05/04/2015 at 09:28 #70785 | |
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Firefly
521 posts |
The only time that cost was mentioned was with regards to comprehensive approach locking or "look back" as we tend to call it. Look back is only provided where required by NR these days and it comes with a price tag.
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| Approach locking 05/04/2015 at 12:38 #70793 | |
DriverCurran
682 posts |
And trust me those 2/3/4/x minutes will be the longest minutes in your entire life.... Paul You have to get a red before you can get any other colour Log in to reply |
| Approach locking 05/04/2015 at 14:31 #70801 | |
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kbarber
1711 posts |
" said:And trust me those 2/3/4/x minutes will be the longest minutes in your entire life.... ...and certainly were at Marylebone in the morning peak, waiting for 21 (the 1967 box) to time off! Log in to reply |
| Approach locking 06/04/2015 at 19:30 #70834 | |
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Muzer
718 posts |
So why with solid state interlocking is this still an issue? Is it simply a case of the testing being expensive due to the increased complexity? I mean, it's not like you need more physical relays and wiring.
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| Approach locking 06/04/2015 at 19:36 #70836 | |
GeoffM
6280 posts |
" said:So why with solid state interlocking is this still an issue? Is it simply a case of the testing being expensive due to the increased complexity? I mean, it's not like you need more physical relays and wiring.Can certainly be complex (which obviously results in more testing) even with CBIs. SimSig Boss Log in to reply |
| Approach locking 06/04/2015 at 19:44 #70837 | |
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Firefly
521 posts |
More design time, more test time and more for the interlocking to process. FF Log in to reply |