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Talk past or route around?

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Talk past or route around? 04/12/2017 at 10:44 #103612
Splodge
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Giantray in post 103610 said:
Steamer in post 103608 said:
Chromatix in post 103607 said:
Which behaviour is more realistic for UK operations? Should this be considered a bug in SimSig?
The behaviour is correct for UK practice- I suspect it would have been altered a long time ago if it wasn't!

I remember reading that on some of the earlier 50s/60s MAS schemes (southern WCML), a signal would show Y onto an unlit signal that would otherwise be showing proceed. Additionally, it was very rare for the top yellow on four aspect signals to be proved, so if the top lamp failed the driver would get the sequence G-> Y-> Y-> R. I don't know if the top lamp is now proved on modern software interlockings.
There are still locations that have this today. Yes today the top yellow is proved, it was also proved in some schemes in the 1970s.
Manchester South SCC works like this; LED style lamps with both lamps able to display three colours which means the red can also be displayed by the top lamp. Unlike most four aspect LED signals, the green aspect is displayed by the top lamp under normal circumstances as well.

It's also relevant from the point of view of this discussion - between Cheadle Hulme and Sandbach, the Manchester South SCC is able to use Bi Directional working when a fault occurs. However, despite being fully fitted in the 'wrong' direction with full TPWS and AWS, the speed is limited to 60mph and approach controlled to the crossovers so there is a huge time penalty in using it. Thus it is often preferred to talk trains through a failure where possible as the time penalties are significant otherwise (especially for stopping trains as you have to wait for passengers to cross to the other platform which is a bit of a trek at Chelford, Holmes Chapel and Goostrey) and cause a lot of disruption in the wider area.

There's the right way, the wrong way and the railway.
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Talk past or route around? 04/12/2017 at 12:22 #103615
Chromatix
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Quote:
if the green aspect was missing in a signal, the Signaller would ensure that this signal only showed a double yellow at the most by a signal held at danger ahead
That's all well and good if there are controlled signals in the right places to do so. What about when it's a long stretch of automatics on plain line? Not every automatic signal has an emergency replacement switch on the panel.

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Talk past or route around? 04/12/2017 at 12:30 #103616
Giantray
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Bonan in post 103605 said:
Not working in the UK, but here in Sweden we are instructed to avoid taking trains past a signal at danger as far as practical for safety reasons. However, of course, sometimes that's not possible without causing major delays.
Passing signals at danger does not affect safety. A Signaller in the UK has very strict rules they must carry out before authorising trains passed signals at Danger. It is perfectly safe and is carried out often.

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Talk past or route around? 04/12/2017 at 12:50 #103617
headshot119
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Giantray in post 103616 said:
Bonan in post 103605 said:
Not working in the UK, but here in Sweden we are instructed to avoid taking trains past a signal at danger as far as practical for safety reasons. However, of course, sometimes that's not possible without causing major delays.
Passing signals at danger does not affect safety. A Signaller in the UK has very strict rules they must carry out before authorising trains passed signals at Danger. It is perfectly safe and is carried out often.
I'm afraid I hugely disagree with that statement!

https://www.gov.uk/raib-reports/derailment-at-knaresborough

Talking a train passed a signal at danger resulted in a derailment. The moment you talk a train past you have lost the vital safety that the interlocking usually provides.

"Platform 1 your Maesteg service. Platform 1A your Aberdare. Platform 2 your London!"
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Talk past or route around? 04/12/2017 at 19:06 #103622
KymriskaDraken
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headshot119 in post 103617 said:
Giantray in post 103616 said:
Bonan in post 103605 said:
Not working in the UK, but here in Sweden we are instructed to avoid taking trains past a signal at danger as far as practical for safety reasons. However, of course, sometimes that's not possible without causing major delays.
Passing signals at danger does not affect safety. A Signaller in the UK has very strict rules they must carry out before authorising trains passed signals at Danger. It is perfectly safe and is carried out often.
I'm afraid I hugely disagree with that statement!

https://www.gov.uk/raib-reports/derailment-at-knaresborough

Talking a train passed a signal at danger resulted in a derailment. The moment you talk a train past you have lost the vital safety that the interlocking usually provides.
It's perfectly safe if everyone is obeying the Rules!

Kev

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Talk past or route around? 04/12/2017 at 19:11 #103623
GeoffM
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Chromatix in post 103615 said:
Quote:
if the green aspect was missing in a signal, the Signaller would ensure that this signal only showed a double yellow at the most by a signal held at danger ahead
That's all well and good if there are controlled signals in the right places to do so. What about when it's a long stretch of automatics on plain line? Not every automatic signal has an emergency replacement switch on the panel.
For a long time it's been a requirement that at least every 4th (or is it a maximum of 4 signals in sequence without ERS?) be fitted with an ERS. However since CBIs came about there is virtually no cost to fitting every automatic signal with an ERS.

So while it's not perfect for older installations, it's not as bad as you imply.

SimSig Boss. Website issues: Check here first: https://www.simsig.co.uk/Wiki/Show?page=newwebsite
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Talk past or route around? 05/12/2017 at 09:31 #103650
kbarber
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GeoffM in post 103623 said:
Chromatix in post 103615 said:
Quote:
if the green aspect was missing in a signal, the Signaller would ensure that this signal only showed a double yellow at the most by a signal held at danger ahead
That's all well and good if there are controlled signals in the right places to do so. What about when it's a long stretch of automatics on plain line? Not every automatic signal has an emergency replacement switch on the panel.
For a long time it's been a requirement that at least every 4th (or is it a maximum of 4 signals in sequence without ERS?) be fitted with an ERS. However since CBIs came about there is virtually no cost to fitting every automatic signal with an ERS.

So while it's not perfect for older installations, it's not as bad as you imply.
I thought it used to be every 5th signal (or on the approach to a particular hazard such as a tunnel or level crossing). So Marylebone (the 1967 box) was able to get away with just one on the up. Neasden South should probably have had one on the down under that requirement, but since the whole installation there predated the requirement I've no idea whether one was retro-fitted. (I visited once, in about 1978, but regrettably never noted such details. John Hinson's diagram https://signalbox.org/diagrams.php?id=254 is for 1940, long before such requirements existed.)

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Talk past or route around? 05/12/2017 at 12:52 #103664
KymriskaDraken
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GeoffM in post 103623 said:
Chromatix in post 103615 said:
Quote:
if the green aspect was missing in a signal, the Signaller would ensure that this signal only showed a double yellow at the most by a signal held at danger ahead
That's all well and good if there are controlled signals in the right places to do so. What about when it's a long stretch of automatics on plain line? Not every automatic signal has an emergency replacement switch on the panel.
For a long time it's been a requirement that at least every 4th (or is it a maximum of 4 signals in sequence without ERS?) be fitted with an ERS. However since CBIs came about there is virtually no cost to fitting every automatic signal with an ERS.

So while it's not perfect for older installations, it's not as bad as you imply.
I vaguely remember that at Bristol Panel we had one ERS each way betwen Bristol and Bath and they weren't the reliable sort.

Kev

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Talk past or route around? 05/12/2017 at 21:30 #103713
GeoffM
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KymriskaDraken in post 103664 said:
I vaguely remember that at Bristol Panel we had one ERS each way betwen Bristol and Bath and they weren't the reliable sort.
7 autos so that's about right.

General question: can you use a non-reliable one to limit aspect reversions - ie we're not stopping trains at it, just trying to prevent a driver getting a black or adverse change of aspect?

SimSig Boss. Website issues: Check here first: https://www.simsig.co.uk/Wiki/Show?page=newwebsite
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Talk past or route around? 05/12/2017 at 21:33 #103714
KymriskaDraken
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GeoffM in post 103713 said:
KymriskaDraken in post 103664 said:
I vaguely remember that at Bristol Panel we had one ERS each way betwen Bristol and Bath and they weren't the reliable sort.
7 autos so that's about right.

General question: can you use a non-reliable one to limit aspect reversions - ie we're not stopping trains at it, just trying to prevent a driver getting a black or adverse change of aspect?
I think you can, as long as someone confirms that the signal is red and it isn't re-cleared. So not really a lot of use.


Kev

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Talk past or route around? 09/12/2017 at 08:27 #103825
Giantray
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GeoffM in post 103713 said:
KymriskaDraken in post 103664 said:
I vaguely remember that at Bristol Panel we had one ERS each way betwen Bristol and Bath and they weren't the reliable sort.
7 autos so that's about right.

General question: can you use a non-reliable one to limit aspect reversions - ie we're not stopping trains at it, just trying to prevent a driver getting a black or adverse change of aspect?
Yes you can Geoff. It is not permitted to use an unreliable one for the protection of the line, eg to protect staff for Line Blockages or Engineer's Possessions, by use of the Emergency Replacement in the box/control centre. It can be used if keyed to danger outside, provided it is visually seen to be at proceed prior to keying to Danger and again visually seen to have gone to danger after keying to danger.

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The following user said thank you: GeoffM