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Wrong workstation displayed in F2 output

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Wrong workstation displayed in F2 output 18/02/2014 at 18:19 #55752
Lyn-Greenwood
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While I was hosting an Exeter multiplay session recently, the person running the Exmouth Junction workstation complained that trains were disappearing/re-appearing on his F2 display window. I had a look on my F2 display and found that some trains in the Exmouth Jn area had incorrect or blank entries in the 'Workstation' column.

In order to investigate further, I put together a simple WTT to see what was going on and found the following when I ran it in non-server mode.

1. Trains departing Honiton for Pinhoe show 'Exmouth Jn', then 'blank', then 'Panel A' and finally 'Exmouth Jn' again. A similar thing happens to trains going towards Honiton.

2. Trains going from Exeter Central to Exmouth show a similar pattern and when they arrive at Exmouth 'Panel A' is shown in the Workstation column.

3. Trains entering Platform 1 at Exeter Central show 'blank' in the column but change to the correct value of Panel B when the train carries out a 'New train' activity.

I'm running with 'v4.0.25' of the Loader and 'v4.3 build 1' of the Exeter sim, which are the current versions.

I've attached 4 saved sessions and the WTT to help investigate the problem. Note that the sessions have a speed of 4X to shorten the time taken for trains to traverse the Honiton single line. To see how the F2 display changes as a train travels along the single line to Honiton, set the F2 refresh rate to 1 second.

Note the F2 output for the ECS at Exmouth and the train waiting in Exeter Central Platform 1. It's also interesting to watch the display for 2L05 as it is leaving Pinhoe. I've tried to give the saved sessions meaningful names to help whoever investigates this strange behaviour.

Lyn

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Wrong workstation displayed in F2 output 18/02/2014 at 18:25 #55753
UKTrainMan
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" said:
I'm running with 'v4.0.25' of the Loader and 'v4.3 build 1' of the Exeter sim, which are the current versions.
The current version of the Loader is v4.0.27 - although I doubt the Loader version has anything at all to do with this issue, which is highly likely to be a simulation-specific issue.

Any views and / or opinions expressed by myself are from me personally and do not represent those of any company I either work for or am a consultant for.
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Wrong workstation displayed in F2 output 18/02/2014 at 19:46 #55756
Peter Bennet
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I've had a look and I know why Honiton shows Exmouth JN - the entry location is coded as such but the TC is not coded at all.

None of the invisible TCs are coded as belonging to any WKS so I can't understand why Panel A suddenly appears, it seems to appear at random and not when a train enters a TC - which would be an obvious thing.

I also can't figure out why it vanishes for trains entering Platform 1 when the train is still on the main line at S310, through trains don't seem to loose the WKS at the same location. Also sending several trains through, there does not seem to be any pattern to when the WKS changes from EJ to B.

So short answer is I have not got a clue why it's doing what it does. Some is undoubtedly down Sim coding - the Honiton- Pinhoe is not coded so should not show any workstation.

Peter

I identify as half man half biscuit - crumbs!
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Wrong workstation displayed in F2 output 18/02/2014 at 20:15 #55759
AndyG
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Peter, is it related to the area defined in WKS being used by default if not implicitly coded in LOC/TCS/SIGs?
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either.
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Wrong workstation displayed in F2 output 18/02/2014 at 20:25 #55761
Peter Bennet
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No can't be in this case looking at the WKS data, it's quite tightly defined.

Peter

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Wrong workstation displayed in F2 output 19/02/2014 at 19:29 #55825
Lyn-Greenwood
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" said:
I've had a look and I know why Honiton shows Exmouth JN - the entry location is coded as such but the TC is not coded at all.

None of the invisible TCs are coded as belonging to any WKS so I can't understand why Panel A suddenly appears, it seems to appear at random and not when a train enters a TC - which would be an obvious thing.

I also can't figure out why it vanishes for trains entering Platform 1 when the train is still on the main line at S310, through trains don't seem to loose the WKS at the same location. Also sending several trains through, there does not seem to be any pattern to when the WKS changes from EJ to B.

So short answer is I have not got a clue why it's doing what it does. Some is undoubtedly down Sim coding - the Honiton- Pinhoe is not coded so should not show any workstation.

Peter
Peter - another strange thing is why the P1 WKS changes to the correct value (and remains correct) when a 'New Train' activity is carried out whereas this doesn't occur at Exmouth where WKS stays at 'Panel A'. Trains travelling along the Exmouth Branch get WKS changed from EJ to Panel A, then to EJ again, then to blank before they reach Topsham. It's as though some other process is somehow corrupting the WKS data value. Do you have a debug facility that could track changes to the WKS value?

There's nothing worse than a random error like this. Solid faults are much easier to find and fix.

Best wishes for your investigation.

Lyn

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Wrong workstation displayed in F2 output 21/02/2014 at 23:34 #55970
GeoffM
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Simple answer to the Exmouth panel issue: there is a hidden signal which was incorrectly allocated. It's working perfectly: it's dodgy data that's the problem :D

For a more technical explanation, the fictional signal was added to suppress approach locking on the long section if the train wasn't within sight of the stop or repeater signals. This was before custom approach locking was added to SimSig so it's just a hangover from long ago.

SimSig Boss
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Wrong workstation displayed in F2 output 22/02/2014 at 05:09 #55975
Hawk777
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This leads to an (to me) obvious question: if that signal doesn’t exist in real life, how does the panel in real life decide whether to apply approach locking to the subsequent real signal? I’m legitimately curious now, from a technical point of view. SimSig shows no track circuits in that section, so I assume there aren’t any in real life either—so how does the panel know whether the signal is within sighting distance or not? Or does Exeter in real life not have comprehensive approach locking, making this whole distinction irrelevant?
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Wrong workstation displayed in F2 output 22/02/2014 at 05:43 #55976
BarryM
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In multi-play,I noticed that trains on the single line Crediton to Barnstaple were appearing on panel A WKS.

Barry

Barry, Sydney, New South Wales, Australia
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Wrong workstation displayed in F2 output 22/02/2014 at 07:59 #55978
Peter Bennet
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If I can maybe add a bit to Geoff's explanation based on a discussion elsewhere. The location is reported based on the next signal the train is due to pass so while the train is on WKS-A but the next signal it is due to pass is on B then it's reporting as B. I suspect the reason it does not report when heading to a bay is that there is no "Next signal". When the new train is created it's now looking at the platform starter which is allocated to a WKS.

The reason I think for the apparent random reporting related to the hidden signals is that they are at coordinates 0,0 which is within the boundaries of WKS-A. Looks like I can remove them anyway.

Or at least that's now my general understanding of the matter.

Peter

I identify as half man half biscuit - crumbs!
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Wrong workstation displayed in F2 output 22/02/2014 at 12:01 #55994
Lyn-Greenwood
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" said:
If I can maybe add a bit to Geoff's explanation based on a discussion elsewhere. The location is reported based on the next signal the train is due to pass so while the train is on WKS-A but the next signal it is due to pass is on B then it's reporting as B. I suspect the reason it does not report when heading to a bay is that there is no "Next signal". When the new train is created it's now looking at the platform starter which is allocated to a WKS.

The reason I think for the apparent random reporting related to the hidden signals is that they are at coordinates 0,0 which is within the boundaries of WKS-A. Looks like I can remove them anyway.

Or at least that's now my general understanding of the matter.

Peter
The Bay Platform WKS problem also shows itself in the West Hampstead sim when you put a train into the Bay Platform at Bedford, so I suspect it will show in all sims that have bay platforms.

Two possible solutions come to mind, but of course they may be difficult or even impossible to implement: 1) if there is no 'next signal', then retain the current WKS value or 2) place a 'hidden signal' at the buffer stops of bay platforms and allocate it to the correct workstation.

By the way, I also noticed on the West Hampstead sim that trains entering at Kempston Hardwick get allocated to Panel 1 instead of Panel 4.

Lyn

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Wrong workstation displayed in F2 output 22/02/2014 at 16:31 #56017
Lyn-Greenwood
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Here's a summary of my thoughts on the WKS allocation subject.

When a train enters a sim, it should be allocated to the workstation which controls the area it will first be approaching and should remain allocated to that workstation until it is about to enter the next workstation's area. This allows the signaller at a workstation which is a 'client' to observe the status of all trains which are in or approaching his/her area. The WKS value should not become 'blank', as this effectively removes it from the client's F2 display, until the train is about to exit the sim.

Trains in Bay Platforms should also retain their WKS value so that a signaller can see how 'joins' and 'divides' are progressing.

Does anyone agree with what I've summarised above?

Lyn Greenwood

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Wrong workstation displayed in F2 output 22/02/2014 at 19:10 #56024
GeoffM
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" said:
This leads to an (to me) obvious question: if that signal doesn’t exist in real life, how does the panel in real life decide whether to apply approach locking to the subsequent real signal? I’m legitimately curious now, from a technical point of view. SimSig shows no track circuits in that section, so I assume there aren’t any in real life either—so how does the panel know whether the signal is within sighting distance or not? Or does Exeter in real life not have comprehensive approach locking, making this whole distinction irrelevant?
The signalling engineers will have wired the interlocking to approach lock when the train passes a certain place, though in practical terms this would be by occupation of a specific track.

SimSig automates the look-back process for developers as it can be horribly complex in areas with lots of pointwork. It implements approach locking when the train passes the last signal unaffected by cancelling a route. However, on a line with 2-aspect signals and repeaters it is a little restrictive. The solution at the time was to add a fictional fixed green signal which prevented the look back from going too far back. At some point after Exeter was released data structures were added allowing the developer to customise the approach locking.

Note that older installations in particular do not have comprehensive approach locking: everything times out regardless of whether a train is approaching.

SimSig Boss
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Wrong workstation displayed in F2 output 22/02/2014 at 19:14 #56025
GeoffM
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" said:
Here's a summary of my thoughts on the WKS allocation subject.

When a train enters a sim, it should be allocated to the workstation which controls the area it will first be approaching and should remain allocated to that workstation until it is about to enter the next workstation's area. This allows the signaller at a workstation which is a 'client' to observe the status of all trains which are in or approaching his/her area. The WKS value should not become 'blank', as this effectively removes it from the client's F2 display, until the train is about to exit the sim.

Trains in Bay Platforms should also retain their WKS value so that a signaller can see how 'joins' and 'divides' are progressing.

Does anyone agree with what I've summarised above?

Lyn Greenwood
A train will appear on a client's list if its next signal is allocated to that panel, or a signal ahead of the train (not necessarily the next one) is red and allocated to that panel. This should also work for bay platforms but requires the exit triangle associated with the track (in most cases it is).

I don't think trains on the fringe area should appear on a client's F2 list until the train becomes relevant - ie approaching one of the client's signals. The server still has control of the train if necessary. A real signaller wouldn't be able to issue instructions to drivers who aren't in their area yet.

SimSig Boss
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