Signal 104 "no overlap available"

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Signal 104 "no overlap available" 25/04/2021 at 13:55 #139031
Albert
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In the attached save, I attempted to set the route out for 6U03 in platform 1 towards Fairwood Jn but got 'no overlap available'. This is a rather odd message in this case as there is no need to set any points in the overlap of signal 104 (the red signal which 7V16 just passed).

I can set the route if I wait until the overlap is clear. It just surprised me that it wouldn't set any earlier.

FWIW, 7V16 came out of Down Yard 7-12.

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Signal 104 "no overlap available" 25/04/2021 at 19:50 #139059
Peter Bennet
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Interesting, the O/L is coded as both a shunt and a main overlap and it appears till one is cleared the other can't be used even though they are identical in all other respects.

Peter

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Signal 104 "no overlap available" 25/04/2021 at 23:06 #139068
GeoffM
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Peter Bennet in post 139059 said:
Interesting, the O/L is coded as both a shunt and a main overlap and it appears till one is cleared the other can't be used even though they are identical in all other respects.
There is a Mantis ticket somewhere for oversetting a shunt onto a main or vice versa. It seems to be quite rare in the UK but quite common in Australia.

SimSig Boss
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Signal 104 "no overlap available" 26/04/2021 at 06:07 #139073
Peter Bennet
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Thanks, I'll need to remind myself where the shunt overlap came from.

Peter

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Signal 104 "no overlap available" 26/04/2021 at 06:49 #139074
Peter Bennet
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I've not got the control tables for Westbury but seems it has been the case (with the Sim) since at least May 2011.

Peter

I identify as half man half biscuit - crumbs!
Last edited: 26/04/2021 at 09:19 by Peter Bennet
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Signal 104 "no overlap available" 26/04/2021 at 11:59 #139082
flabberdacks
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GeoffM in post 139068 said:
Peter Bennet in post 139059 said:
Interesting, the O/L is coded as both a shunt and a main overlap and it appears till one is cleared the other can't be used even though they are identical in all other respects.
There is a Mantis ticket somewhere for oversetting a shunt onto a main or vice versa. It seems to be quite rare in the UK but quite common in Australia.
31615

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Signal 104 "no overlap available" 13/07/2021 at 12:40 #140548
Dionysusnu
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This also happens with the call-on route at Saltley S194 to S200, because the call-on route includes an overlap, for some reason.
Last edited: 13/07/2021 at 15:46 by Dionysusnu
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Signal 104 "no overlap available" 13/07/2021 at 15:27 #140549
Albert
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I can't find 194 nor 200 on the signal number plan of Saltley, would you mind indicating whereabouts these signals are?
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Signal 104 "no overlap available" 13/07/2021 at 15:45 #140550
Dionysusnu
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B'ham Moor Street into Snow Hill, platform 2
Last edited: 13/07/2021 at 16:31 by Dionysusnu
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Signal 104 "no overlap available" 13/07/2021 at 17:02 #140551
Albert
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You mean that the call-on route cannot be set if the overlap of a previous train into the platform is not clear yet?
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Signal 104 "no overlap available" 13/07/2021 at 17:06 #140552
Dionysusnu
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Precisely. That overlap is quite slow to time out.
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Signal 104 "no overlap available" 13/07/2021 at 18:06 #140555
GeoffM
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Albert in post 140551 said:
You mean that the call-on route cannot be set if the overlap of a previous train into the platform is not clear yet?
Dionysusnu in post 140552 said:
Precisely. That overlap is quite slow to time out.
Long platform, 15mph, around 60s timeout*. Seems about right to me without seeing the control tables - though I wouldn't be surprised if it's actually too short and should be more like 120s like a lot of others like this.

* Rule of thumb is to take the TC length in metres, divide by the max speed in m/s, and add half on again to get the overlap release time in seconds. However, there are shorter times, and there are longer times. Just depends on a number of variables.

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Signal 104 "no overlap available" 17/08/2021 at 20:10 #141186
Guts
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I don't know if I should start a new thread for this.

Is there any reason S277 from the East Somerset line has an overlap? Is it a passenger line?

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Signal 104 "no overlap available" 17/08/2021 at 20:42 #141188
GeoffM
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Guts in post 141186 said:
I don't know if I should start a new thread for this.

Is there any reason S277 from the East Somerset line has an overlap? Is it a passenger line?
I don't know why nearly the whole has overlaps - perhaps aspirations for passenger service? - but this photo shows them (see the little arrows).


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Signal 104 "no overlap available" 18/08/2021 at 07:41 #141196
clive
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Particularly in the case of DS2/US2, I wonder if it's extra protection for the single-line working.
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Signal 104 "no overlap available" 18/08/2021 at 12:42 #141200
Dionysusnu
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On a slightly related note, why is S275 approach controlled for all routes? They both seem to be straight, or at least no speed reduction.
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Signal 104 "no overlap available" 18/08/2021 at 13:08 #141201
Hap
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Dionysusnu in post 141200 said:
On a slightly related note, why is S275 approach controlled for all routes? They both seem to be straight, or at least no speed reduction.
There is a speed reduction from 30 to 20 on to the U/DGL and 25 for the main route off of the branch, protecting a 100mph mainline.

HAP
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Signal 104 "no overlap available" 18/08/2021 at 16:26 #141204
Stephen Fulcher
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Also saves a timeout if the Signaller changes his mind and the train hasn’t got there yet
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