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Acle two aspect colour light signal A20

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Acle two aspect colour light signal A20 08/04/2016 at 18:07 #81722
Underwood
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748 posts
Hello all,

I'm writing a script for another virtual cab ride along the Wherry Lines. I note that signal 'A 20' (in the Down direction, towards Acle station) is a two aspect repeater, and is the only one in the area.

I can only guess it's a colour and not a distant because there is no signal box control in the section before, as the only signals before are operated by Chapel Road/Station Road crossings at Lingwood, and aren't block signals, so in affect you are entering a signal controlled area from a non-signal controlled area, or something along those lines?

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?

If anyone could help in how I could write it into a script that would be most helpful, otherwise I could end up with a thousand paragraphs trying to explain it


Any help is much appreciated!


James.

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Acle two aspect colour light signal A20 08/04/2016 at 18:18 #81723
madaboutrains
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Distant signals show to the driver that when the distant is off all the homes will be too. If the distant is on he must be ready to stop at the first home signal.
RIP Feltham Panel 1
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Acle two aspect colour light signal A20 08/04/2016 at 19:55 #81724
Steamer
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3984 posts
" said:
Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
You've got yourself in a bit of a muddle there. Distant signals aren't related to Absolute Block. Of course, most areas with semaphores still use Absolute Block, but it's perfectly possible to have colour lights with AB and semaphores with TCB.

Quote:
I can only guess it's a colour and not a distant because there is no signal box control in the section before, as the only signals before are operated by Chapel Road/Station Road crossings at Lingwood, and aren't block signals, so in affect you are entering a signal controlled area from a non-signal controlled area, or something along those lines?
The line is 'signal controlled' throughout. The single line is controlled jointly by Brundall Jn and Acle boxes, and the signals there are block signals. The level crossing signals, as you rightly say, are non-block, but the line is still controlled by Brundall/Acle. Remember, the signalling arrangement must 'appear' correctly to the driver- they obey signals regardless of whether they're block or non-block.

Signal 20 is a (colour light) distant signal. It can be cleared if all of Acle's stop signals in that direction, that is to say 19, 17 and 16, are clear.

"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)
Last edited: 08/04/2016 at 19:56 by Steamer
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Acle two aspect colour light signal A20 08/04/2016 at 19:57 #81725
Finger
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" said:
Distant signals show to the driver that when the distant is off all the homes will be too. If the distant is on he must be ready to stop at the first home signal.

Not only all of the homes, but the starter, too - in a purely mechanical box. With color light signals which can show yellow, it may be different.

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Acle two aspect colour light signal A20 08/04/2016 at 20:58 #81726
clive
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2789 posts
" said:

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
A semaphore distant and a colour-light distant serve the same role in signalling: they indicate to the driver whether all stop signals controlled by the signal box are off. (There are special cases, but that's the general rule.)

Distants often got converted to colour-light while leaving the rest of the signals as semaphores for two main reasons:
(1) They're the most important warning to the driver - they offer braking distance warning of a danger signal - so they need to be as visible as possible.
(2) They're the furthest from the signal box, so tend to be the hardest lever to pull if semaphore.

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Acle two aspect colour light signal A20 08/04/2016 at 21:31 #81727
jc92
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3685 posts
" said:
" said:

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
A semaphore distant and a colour-light distant serve the same role in signalling: they indicate to the driver whether all stop signals controlled by the signal box are off. (There are special cases, but that's the general rule.)

Distants often got converted to colour-light while leaving the rest of the signals as semaphores for two main reasons:
(1) They're the most important warning to the driver - they offer braking distance warning of a danger signal - so they need to be as visible as possible.
(2) They're the furthest from the signal box, so tend to be the hardest lever to pull if semaphore.
Croes Newyydd North Fork Being a big exception. prior to resignalling, its down distant was a motor worked Semaphore reading to a colour light home! its the only one if its type I can think of.

"We don't stop camborne wednesdays"
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Acle two aspect colour light signal A20 08/04/2016 at 21:49 #81728
headshot119
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4869 posts
" said:
" said:
" said:

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
A semaphore distant and a colour-light distant serve the same role in signalling: they indicate to the driver whether all stop signals controlled by the signal box are off. (There are special cases, but that's the general rule.)

Distants often got converted to colour-light while leaving the rest of the signals as semaphores for two main reasons:
(1) They're the most important warning to the driver - they offer braking distance warning of a danger signal - so they need to be as visible as possible.
(2) They're the furthest from the signal box, so tend to be the hardest lever to pull if semaphore.
Croes Newyydd North Fork Being a big exception. prior to resignalling, its down distant was a motor worked Semaphore reading to a colour light home! its the only one if its type I can think of.
It was unique I believe at the time it was decommissioned, being the last on the network.

"Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer
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Acle two aspect colour light signal A20 09/04/2016 at 08:20 #81736
kbarber
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Online
" said:
" said:
" said:

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
A semaphore distant and a colour-light distant serve the same role in signalling: they indicate to the driver whether all stop signals controlled by the signal box are off. (There are special cases, but that's the general rule.)

Distants often got converted to colour-light while leaving the rest of the signals as semaphores for two main reasons:
(1) They're the most important warning to the driver - they offer braking distance warning of a danger signal - so they need to be as visible as possible.
(2) They're the furthest from the signal box, so tend to be the hardest lever to pull if semaphore.
Croes Newyydd North Fork Being a big exception. prior to resignalling, its down distant was a motor worked Semaphore reading to a colour light home! its the only one if its type I can think of.

Latchmere Junction used to be the same on the up (towards Clapham/Stewarts Lane). In that case there was no TC or aspect control of any kind on the distant - it was just the interlocking from the home signal lever, resulting in an alarm being provided to remind you if you hadn't put the distant back by the time the train passed the home. I wonder if North Fork was similar?

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Acle two aspect colour light signal A20 09/04/2016 at 16:38 #81743
headshot119
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4869 posts
" said:
" said:
" said:
" said:

Do you need a colour light distant before entering an absolute block section rather than starting off with a distant?
A semaphore distant and a colour-light distant serve the same role in signalling: they indicate to the driver whether all stop signals controlled by the signal box are off. (There are special cases, but that's the general rule.)

Distants often got converted to colour-light while leaving the rest of the signals as semaphores for two main reasons:
(1) They're the most important warning to the driver - they offer braking distance warning of a danger signal - so they need to be as visible as possible.
(2) They're the furthest from the signal box, so tend to be the hardest lever to pull if semaphore.
Croes Newyydd North Fork Being a big exception. prior to resignalling, its down distant was a motor worked Semaphore reading to a colour light home! its the only one if its type I can think of.

Latchmere Junction used to be the same on the up (towards Clapham/Stewarts Lane). In that case there was no TC or aspect control of any kind on the distant - it was just the interlocking from the home signal lever, resulting in an alarm being provided to remind you if you hadn't put the distant back by the time the train passed the home. I wonder if North Fork was similar?
North Forks distant was worked off the same lever as the home. Though a emergency replacement switch was provided on the distant. I suspect occupancy of the berth track automatically put the distant back, and in any case it would go back as soon as you put the home back.

"Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer
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Acle two aspect colour light signal A20 09/04/2016 at 19:24 #81749
nnr
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170 posts
From the horse's mouth.....................

A20 is the down distant. It is a colour light (as opposed to a semaphore distant as per the up road No.1) and shows a yellow or green aspect, depending on the state of the associated down road signals.

The section from Brundall to Yarmouth via Acle is split into two block sections, Brundall Jnc to Acle and Acle to Yarmouth Vauxhall. Both sections are worked on acceptance levers with each box having an acceptance lever. When the lever is pulled in say Yarmouth, Yarmouth is accepting a train in Acle and the lever in Acle box will be normal. Both sections are worked under Track Circuit Block regulations.

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Acle two aspect colour light signal A20 12/04/2016 at 13:36 #81797
Underwood
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748 posts
Thank you very much guys for the contributions!

The signal is some distance away, somehow didn't think about the theory that the further away it is, the harder the lever would be to pull, thanks for that Clive

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