Signal visibility during thick fog?

[SpacePhoenix]

Cornwall another area with semaphores?

 

[Yabbadabba]

The Sussex East Coast is just about hanging on to its semaphores and I still remember double blocking during foggy weather when I used to work those boxes.

 

[NSEFAN]

Cornwall another area with semaphores?

From my recent travels around Cornwall on FGW and XC, fog is definitely not required for trains to be delayed.

 

[Starmill]

Both an OFF indicator and a banner repeater are provided at some loactions though, such as Platform 4 at Stalybridge.

 

[MarkyT]

Both an OFF indicator and a banner repeater are provided at some loactions though, such as Platform 4 at Stalybridge.

Banners are provided for drivers where even from the cab a signal isn't easily visible from a normal stopping point along a platform. Sometimes that banner is also sufficient for the guard or platform dispatch staff to see the signal state. If not an OFF indicator is provided as well. Often a signal is perfectly visible to the driver but can't be seen by the guard from the usual dispatch position perhaps because it's on the other side of the track. Only an OFF indicator is required in that case.

 

[Llanigraham]

There are no semaphores anywhere I (and most other train drivers) drive trains but dont let that stop you looking for some silly little exception to get your point across will you! :roll:

What a stupid comment!
Just because your route doesn't have them doesn't mean there are plenty left in the rest of the country.
To add to the list, The Marches main line from Abergavenny north to beyond Shrewsbury.

 

[oliMw]

A few lines around Norfolk/Suffolk have them too :roll:

 

[ac6000cw]

The main reasons the GWR developed their 'ATC' system more than an century ago (a now obsolete AWS system) was that it avoided the need for trains to slow down and the need to call out 'fog signalmen' (who placed detonators on the rail when necessary) in foggy weather. This saved money in the long run via improved efficiency and safety - the GWR was almost entirely semaphore signalled for most of it's life.
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A few lines around Norfolk/Suffolk have them too :roll:

....not forgetting the major installation around the Barnetby area of course - four running lines and a three way junction - and most of the Ely-March-Peterborough route.

 

[Tomnick]

Even better - five running lines between Barnetby and Wrawby, the Down Goods being particularly interesting in that the section signal is a free pull (no 'line clear' release), one of very few (three or four?) in the country to be so.

 

[muz379]

Banners are provided for drivers where even from the cab a signal isn't easily visible from a normal stopping point along a platform. Sometimes that banner is also sufficient for the guard or platform dispatch staff to see the signal state. If not an OFF indicator is provided as well. Often a signal is perfectly visible to the driver but can't be seen by the guard from the usual dispatch position perhaps because it's on the other side of the track. Only an OFF indicator is required in that case.

Platform 4 at stalybridge is anomalous to this because the Banner Repeater can be seen very clearly by the guard from their position at the rear of the train dispatching . I would know as a guard who works from there often

The only thing I can think of is that the BR is obscured from view to the guard at the rear of a 6 car tpe train working from there hence the provision of the off indicator .

either that or the off is provided for guards because banner repeaters dont convey any authority for a train to stop or proceed the guard could dispatch past a BR repeating a stop aspect but if the train drew up to the signal in question it might also still be within the platform

 

[ac6000cw]

Even better - five running lines between Barnetby and Wrawby, the Down Goods being particularly interesting in that the section signal is a free pull (no 'line clear' release), one of very few (three or four?) in the country to be so.

Is that because the Down Goods is operated permissively (or was in the past) ?

 

[MarkyT]

Platform 4 at stalybridge is anomalous to this because the Banner Repeater can be seen very clearly by the guard from their position at the rear of the train dispatching . I would know as a guard who works from there often

The only thing I can think of is that the BR is obscured from view to the guard at the rear of a 6 car tpe train working from there hence the provision of the off indicator .

either that or the off is provided for guards because banner repeaters dont convey any authority for a train to stop or proceed the guard could dispatch past a BR repeating a stop aspect but if the train drew up to the signal in question it might also still be within the platform

I think your first explanation of different length trains is probably correct. In a related way at Waterloo in London some of the higher numbered platforms have banners. This is clearly of no use to 12 car (10 car 444) drivers as they are well forward of the banner with the cab almost in line with the signal. The driver of a short 4 or 5 car train departing from the buffers however can't see the signal at all, hence the banner is definitely required and, mounted as they are quite high above the platform, they are also perfecly visible to the guard for dispatch as well. A cross disciplinary "sighting commitee" involving train crew representatives is responsible for agreeing all this for any new signalling project. It's possible in older installations that additional indicators were provided for particular manoeuvres or train lengths that are no longer common today, but the indicators wouldn't be removed as long as they weren't causing a hazard.

 

[Tomnick]

Is that because the Down Goods is operated permissively (or was in the past) ?

It could well have been, once upon a time - I was hoping that some of my photos might give a clue (through the face of the Down Goods block instrument), but they don't. It's certainly not permissive nowadays though.

 

[455driver]

Banners are provided for drivers where even from the cab a signal isn't easily visible from a normal stopping point along a platform. Sometimes that banner is also sufficient for the guard or platform dispatch staff to see the signal state. If not an OFF indicator is provided as well. Often a signal is perfectly visible to the driver but can't be seen by the guard from the usual dispatch position perhaps because it's on the other side of the track. Only an OFF indicator is required in that case.

That doesnt work with some new BR instalations because the BR will revert to on when the train passes it even though the signal is off, platform 4 at Basingstoke is a case in point, or it was when it was resignalled.

 

[MarkyT]

That doesnt work with some new BR instalations because the BR will revert to on when the train passes it even though the signal is off, platform 4 at Basingstoke is a case in point, or it was when it was resignalled.

Interesting. Are the new banners at Basingstoke on the running in ends of the canopies? I assume you're mentioning this because the pl.4 one is actually visible from positions a guard could be dispatching from. It's unlikely a project would provide a track circuit joint part way along a platform solely to auto-replace a banner*, although platforms are sometimes split into two or more track circuit sections for other reasons, to help signallers gauge the available length for joining for example, and that might be relevant at Basingstoke with the carriage sidings nearby. If the banner in this case is no good for dispatching, is there a separate OFF indicator provided as well?

* Working on track level signalling equipment through platforms is a particular maintenance headache. It's neccessary to obtain possessions, stopping traffic because there are no easily accessible safe refuge areas. Just as in tunnels and on bridges, good design should minimise the equipment count in those areas.

In a similar way to distant signals, automatically replacing banner signals ASAP after a train has passed them is not an absolute requirement and additional equipment just to do that shouldn't be provided. For distant signals, standards suggest the next track circuit boundary encountered (provided for other purposes) should be used, and I assume the same would be applied for regular 'running' banners away from stations where there's no dispatch issue. Platforms should be treated as a special case though with dispatch requirements taken into account, and perhaps the need for a separate additional OFF indicator avoided in some cases.

 

[455driver]

Interesting. Are the new banners at Basingstoke on the running in ends of the canopies? I assume you're mentioning this because the pl.4 one is actually visible from positions a guard could be dispatching from. It's unlikely a project would provide a track circuit joint part way along a platform solely to auto-replace a banner*, although platforms are sometimes split into two or more track circuit sections for other reasons, to help signallers gauge the available length for joining for example, and that might be relevant at Basingstoke with the carriage sidings nearby. If the banner in this case is no good for dispatching, is there a separate OFF indicator provided as well?

* Working on track level signalling equipment through platforms is a particular maintenance headache. It's neccessary to obtain possessions, stopping traffic because there are no easily accessible safe refuge areas. Just as in tunnels and on bridges, good design should minimise the equipment count in those areas.

In a similar way to distant signals, automatically replacing banner signals ASAP after a train has passed them is not an absolute requirement and additional equipment just to do that shouldn't be provided. For distant signals, standards suggest the next track circuit boundary encountered (provided for other purposes) should be used, and I assume the same would be applied for regular 'running' banners away from stations where there's no dispatch issue. Platforms should be treated as a special case though with dispatch requirements taken into account, and perhaps the need for a separate additional OFF indicator avoided in some cases.

Yes the BR is at the running in end, yes it goes back as soon as the train passes it and yes there is an off indicator provided.
Basingstokes main platforms used by SWT are all 12 coaches long.

 

[swt_passenger]

Yes the BR is at the running in end, yes it goes back as soon as the train passes it and yes there is an off indicator provided.
Basingstokes main platforms used by SWT are all 12 coaches long.

At one stage there was also a notice at the country end reminding guards to disregard the banner and view the starter signal, not sure if it is still there though.

I remember there was quite a long discussion about it at the time the new signalling was commissioned in another forum...

 

[TDK]

This is also my understanding , the visual indication coupled with the AWS sounding a warning would indicate the repeated signal was at caution or preliminary caution, no AWS and the repeated signal is on proceed .

Many starter signals do not have AWS and on many stations the stop mark is past the AWS magnet so you cannot rely on AWS to be fair.
--- old post above --- --- new post below ---

OFF indicators are specifically for staff despatching trains, banner repeaters for signal sighting where visibility is permanently restricted. Neither is specifically fog related.

There are OFF indicators in the 4 foot at Liverpool Lime Street or used to be and these could only be seen by drivers so I would say they were installed for drivers.

 

[D107]

And in the midlands, quite a lot in fact

A lot of semaphores have sadly disappeared in South Wales of late but Tondu (on the Maesteg branch out of Bridgend) is still "as was". Any search for photos of the "Taffy Tug 2" railtour should show the necessary.

 

[muz379]

Many starter signals do not have AWS and on many stations the stop mark is past the AWS magnet so you cannot rely on AWS to be fair.

I wasnt just talking about starter signals I was talking about signals in general .

And even if the magnet was after the stop mark the signal aspect would have to be ascertained prior to the train starting so no you would not rely on AWS .

 

[455driver]

At one stage there was also a notice at the country end reminding guards to disregard the banner and view the starter signal, not sure if it is still there though.

I remember there was quite a long discussion about it at the time the new signalling was commissioned in another forum...

Yes there was and the consensus was that the new way was silly.

 

[MarkyT]

Yes there was and the consensus was that the new way was silly.

I agree, and I suspect it isn't even consistent on new schemes. I looked at the rule book on dispatch and it only mentions signals and OFF indicators. There is no talk of banners at all. I would argue a banner is a valid substitute for a signal for dispatch purposes just as it is for driving purposes and the fact they actively have to tell guards to ignore the banner tends to support this. The only possible reason for wanting auto-replacement is to avoid drivers reading through from a signal on approach or on a parallel track but I can't really imagine a particular scenario. For trains passing fast through the platform the banner would be replaced very quickly anyway once the starting signal it repeats was replaced as the train passed that. For a train standing in the platform there'd be a train in the way. As I said before you wouldn't provide a track joint in the platform solely to replace the banner, so some through platform banners even in modern schemes wouldn't replace whereas others including this one clearly do. I would argue that a banner, an OFF indicator and a notice saying ignore the banner is too much information, as well as extra equipment to maintain. Probably not dangerous but nevertheless rather daft.

 

[Tomnick]

For a train standing in the platform there'd be a train in the way.

Isn't that the potential risk that the principle of banners being replaced automatically is trying to minimise though? Train entering platform after being talked by the signal in rear (or under the authority of a sub, but Huddersfield Control should prevent that), seeing the banner off and accelerating, overlooking the presence of a train between the banner and the signal itself?

 

[MarkyT]

Isn't that the potential risk that the principle of banners being replaced automatically is trying to minimise though? Train entering platform after being talked by the signal in rear (or under the authority of a sub, but Huddersfield Control should prevent that), seeing the banner off and accelerating, overlooking the presence of a train between the banner and the signal itself?

If a signaller is authorising a move past a red signal, they should be aware of the state of the platform ahead and the nature of the movement intended which should be agreed clearly with the driver. I know a track circuit failure may be the reason for the talk-by, and that could mean the signaller may not be absolutely certain there are no vehicles there, but if they had any inkling then why would they be setting a forward route or not advising extreme caution to the approaching driver being talked by? They could in any case check with platform staff. If the track circuit failure preventing a main clearance for a through train nevertheless allowed clearance of the associated call-on (using the same entrance - exit buttons remember) then Huddersfield controls would apply, with the forward route not set and the platform starter and banner on anyway.

I agree that away from stations, where there can be no absolute/permissive confusion, banners and distants should be replaced at the next available track circuit, even sometimes providing extra sections just to achieve that say on sharp curves in cuttings etc where short trains could hide at signals. That does help control risk in areas where speed of talk-by movements could be higher, access in emergency could be more difficult and there are no station staff to ask about the state of the platform track. At stations with absolute/permissive platforms however, any ambiguity is controlled by the Huddersfield feature, so the platform banner need not be auto-replacing. Many banners in non permissive platforms do not auto-replace earlier than their associated signal, where the next available joint is at the platform starting signal, even its overlap in the case of an automatic.

Another idea would be to make the banners last wheel replaced in these platforms. In the case of a long train, it's rear end (where the guard seeing the banner is, by definition) has not yet passed the banner so it will still be displaying off. In a data driven interlocking the slightly greater control complexity would be a negligible hardship.

 

[455driver]

Any time I am talked past a signal my train remains at caution until it has passed the next (proceed) signal, I dont accelerate until I am 100% certain that the section is clear and that section doesnt end until I pass the next signal.

Okay it will cause a bit more delay but much better that than the other!

 

[carriageline]

I completely agree 455driver. And as a signaller that's what I expect. With track circuit failures, you have no idea what's down there, and you could have 100 trains go over it, and then a trolley pushed on the line. TC is already showing occupied so no body would know. Degraded working requires caution at every turn!

Plus, we have to be sure the section is clear (apart from specific situations, assisting trains, initial examination of a TCF etc) otherwise we won't talk you past the signal. We can't be unsure if there is a train in there or not before talking another train past, you can have an 'authorised' person to tell you if train has arrived with rail lamp, or we could watch the TC in advance occupy then clear, but I personally would never put a train into a TCF section if I was unsure the previous train had left.


Sent from my iPhone using Tapatalk

 

[Tomnick]

I agree fully with both (edit: all three of you by the time I posted it!) of you - the risk of a train approaching a cleared banner repeater in those circumstances should be minimal (as a result of the combination of the signalman acting correctly, Huddersfield control and the driver continuing at caution right through the section - sod the delay, that's entirely the correct approach!), so it sounds to me like one of those standards that's applied 'where possible' to address that tiny risk but not where that's involve any significant extra spending. Sadly, it seems to me (please correct me if I'm wrong!) that signalling designer slavishly follow the standards without any thought as to whether they're actually appropriate and whether any deviation is necessary - that would explain this case, and it'd also explain the ground frame on our patch (trailing connection on the 'branch' beyond what's now a conventional double junction, yet any movement being made legitimately through that connection immediately replaces signals to danger - in front of trains - on both 'main' lines...guess how we found this out?!).

 

[455driver]

it seems to me (please correct me if I'm wrong!) that signalling designer slavishly follow the standards without any thought as to whether they're actually appropriate and whether any deviation is necessary -

Which would probably be okay if the standards reamined the same, each resignalling seems to work to a different set of standards.
We had the Portsmouth (Havant) area which was axle counters and conventional signal heads, then we had Basingstoke which was track circuits and LED heads.

that would explain this case, and it'd also explain the ground frame on our patch (trailing connection on the 'branch' beyond what's now a conventional double junction, yet any movement being made legitimately through that connection immediately replaces signals to danger - in front of trains - on both 'main' lines...guess how we found this out?!).

is there a prize for guessing correctly!

 

[Tomnick]

Give it your best shot - I'm sure it's worth a pint at some unspecified point in the future, as long as the opposite applies for a wrong guess .

 

[455driver]

Give it your best shot - I'm sure it's worth a pint at some unspecified point in the future, as long as the opposite applies for a wrong guess .

Oh I dont know about that!