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Locking problem 01/07/2020 at 19:54 #128752 | |
grahamj42
130 posts |
AN53 (Liverpool South Parkway down fast starter) locks points 48 both ways. This doesn't seem right and causes delays when a down train from Hut's Cross crosses an up train for Weaver Junction. The problem existed in the pre-loader V5 version. Log in to reply |
Locking problem 01/07/2020 at 20:15 #128753 | |
GeoffM
6344 posts |
Agreed, that doesn't look right. Mantis 30959.
SimSig Boss Log in to reply |
Locking problem 01/07/2020 at 22:45 #128757 | |
CGP
1 posts |
It may be the Route Holding principle from the old Allerton Junction mechanical interlocking? To quote an old BRB Training Manual on mechanical interlocking "Levers operating stop signals next in advance of trailing points operated from the same box should, when operated, lock such point levers in either position, unless the locking will unduly interfere with traffic movements for which there is adequate space between the signals and the points concerned" Hope this helps Log in to reply |
Locking problem 02/07/2020 at 04:07 #128772 | |
headshot119
4869 posts |
grahamj42 in post 128752 said:AN53 (Liverpool South Parkway down fast starter) locks points 48 both ways. This doesn't seem right and causes delays when a down train from Hut's Cross crosses an up train for Weaver Junction.Graham, it's accurate to the mechanical locking, AN53 off did indeed lock the points both ways. "Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Log in to reply The following user said thank you: grahamj42 |
Locking problem 02/07/2020 at 06:23 #128774 | |
GeoffM
6344 posts |
I forgot that was a mechanical box!
SimSig Boss Log in to reply |
Locking problem 02/07/2020 at 14:15 #128793 | |
grahamj42
130 posts |
Thanks everybody. I should have done more research to see whether Allerton was still a mechanical box. A note in the manual would be nice. Log in to reply |
Locking problem 02/07/2020 at 16:21 #128806 | |
jc92
3649 posts |
grahamj42 in post 128793 said:Thanks everybody. I should have done more research to see whether Allerton was still a mechanical box.from the manual (under one touch routes) "With the exceptions of Ditton, Edge Hill and Lime St, all of the signal boxes in the area are mechanical boxes, operated by a standard lever frame." "We don't stop camborne wednesdays" Log in to reply |
Locking problem 02/07/2020 at 21:46 #128836 | |
Steamer
3958 posts |
CGP in post 128757 said:It may be the Route Holding principle from the old Allerton Junction mechanical interlocking? To quote an old BRB Training Manual on mechanical interlockingWhat was the logic behind this? The only benefit I can see is preventing a signaller moving the trailing points under a passing train- but in any case, the points in question are locked by a track circuit? It does seem to add a lot of operational headaches to a layout. grahamj42 said: A note in the manual would be nice.Note added to warn about AN53 back locking. "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 The following users said thank you: headshot119, grahamj42 |
Locking problem 03/07/2020 at 09:46 #128852 | |
kbarber
1723 posts |
Steamer in post 128836 said:CGP in post 128757 said:I think it derives from the regulatory requirements (probably written when the regulator was still the Board of Trade). These things often ended up staying in the requirements long after the need for them had gone. (And of course - though I'm aware this wasn't the case at Allerton, which I believe was an LMR installation at the time of electrification - boxes often lasted a long time and relocking of frames tended to be done rather sparingly, given the skill needed of a locking fitter and the disruption to traffic while the interlocking was disarranged.)It may be the Route Holding principle from the old Allerton Junction mechanical interlocking? To quote an old BRB Training Manual on mechanical interlockingWhat was the logic behind this? The only benefit I can see is preventing a signaller moving the trailing points under a passing train- but in any case, the points in question are locked by a track circuit? It does seem to add a lot of operational headaches to a layout. Log in to reply |
Locking problem 03/07/2020 at 10:39 #128859 | |
clive
2766 posts |
Steamer in post 128836 said:CGP in post 128757 said:It predates track circuiting being common and the concept of sectional route locking.It may be the Route Holding principle from the old Allerton Junction mechanical interlocking? To quote an old BRB Training Manual on mechanical interlockingWhat was the logic behind this? The only benefit I can see is preventing a signaller moving the trailing points under a passing train- but in any case, the points in question are locked by a track circuit? It does seem to add a lot of operational headaches to a layout. On a pure mechanical layout, you need some way to prevent points between two signals being moved under the train or as the train approaches them. Facing points will have a lock that includes a fouling bar, so you put the FPL lock in the locking for the signal in rear and require that signal to stay off until the train has reached the last facing points. But trailing points might well not have a FPL. So a reasonable approach is to keep them locked when the signal in advance is clear, because that's when a train could go over them at speed, making a derailment more likely if they're moved. Once you've got track circuits you can track-lock the points, but that doesn't prevent them being moved as a train is approaching them at speed. For that, you need sectional locking that holds the points while any track circuit between the signal in rear and the points is occupied, plus a timeout on the signal in rear being replaced. That's what we get on relay and SSI interlockings and we're all used to it in SimSig. If it's fitted to a mechanical box, the SBSI can always override the general rule. Log in to reply The following user said thank you: grahamj42 |
Locking problem 03/07/2020 at 10:53 #128860 | |
Stephen Fulcher
2055 posts |
As an example, Banbury South has all the points on the Up Main backlocked by BS5 signal even after the track circuiting and sectional locking was electrically applied. It was never removed because of the cost involved, and was a menace as the points exiting the Up Goods were also in the Up Main clearing point so you couldn’t accept another train from the North until the goods train was long gone. As a result some Signalmen used to let freights out of the loop upto a red at BS5 (Which was a fair way away) and then normalise the points behind the train before pulling 5.
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Locking problem 03/07/2020 at 12:13 #128868 | |
jc92
3649 posts |
Exeter west has the same arrangement with 52,53 and 54 points on the down goods which are locked by 122 (the down main section signal) as they aren't track circuited and the system therefore can't prove its safe to move them until 122 has been returned to danger. As Stephen says, sometimes putting a train out to 122 at danger is the better option if an up train is approaching to prevent delaying it while a slow moving goods clears 122 which is a fair distance away from the box. "We don't stop camborne wednesdays" Log in to reply |
Locking problem 03/07/2020 at 13:09 #128871 | |
Andrew G
550 posts |
jc92 in post 128868 said:Exeter west has the same arrangement with 52,53 and 54 points on the down goods which are locked by 122 (the down main section signal) as they aren't track circuited and the system therefore can't prove its safe to move them until 122 has been returned to danger.There is an alternative. 53 isn't back locked by 122 but is locked by a Track Circuit. If you put 53 AND 43 back after train has passed you will find 52 and 54 are no longer back locked by 122. Last edited: 03/07/2020 at 13:09 by Andrew G Reason: None given Log in to reply |
Locking problem 04/07/2020 at 01:29 #128954 | |
grahamj42
130 posts |
jc92 in post 128868 said:Exeter west has the same arrangement with 52,53 and 54 points on the down goods which are locked by 122 (the down main section signal) as they aren't track circuited and the system therefore can't prove its safe to move them until 122 has been returned to danger.This has been bugging me since I bought the Exeter West simulation as it blocks the up passenger lines. It seems ironic in that the down goods train passes directly in front of the box. I did once find the technique Andrew G describes, but forgot to write it down. Log in to reply |
Locking problem 04/07/2020 at 01:36 #128955 | |
jc92
3649 posts |
grahamj42 in post 128954 said:jc92 in post 128868 said:I was passed to work the box and I've never picked up on that one! Much appreciated Andrew.Exeter west has the same arrangement with 52,53 and 54 points on the down goods which are locked by 122 (the down main section signal) as they aren't track circuited and the system therefore can't prove its safe to move them until 122 has been returned to danger.This has been bugging me since I bought the Exeter West simulation as it blocks the up passenger lines. It seems ironic in that the down goods train passes directly in front of the box. "We don't stop camborne wednesdays" Log in to reply |