I was in Manchester Piccadilly today and whilst awaiting my train to Doncaster I observed the departure of a train on the opposite platform. The Guard of the train was awaiting a green/amber signal and I noticed how far away the signal was at the top end of the platform. This got me wondering if this signal would actually be visible during thick fog and what would the procedure be if the signal was not visible? I assume the signals must have some sort of special lighting as I don't ever recall the rail network grinding to a halt during thick fog! Many thanks.
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Signal visibility during thick fog?
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Without knowing the state at Piccadilly the guard probably was watching for an OFF indicator rather than the signal itself. At big stations with complex throats and many chances for cross reading signals these are provided somewhere along the platform where they can only be easily seen on the relevant platform. They sort of repeat the signal, if the signal is showing a red aspect (being ON) the indicator will be unlit, if showing any proceed aspect (not sure about subsidiary aspects though) they will be lit and show the word "OFF". Banner repeaters are sometimes used, same theory, horizontal when signal on, 45 degrees when off.
If a guard cannot see a signal and no indicator is provided then they are expected to get into a position where they can see them. In short, walk along the platform until its visible. In theory a call can be made to the controlling signaller but I believe the signaller cannot say the signal is off but that it is "set in your favour" or words to that effect.
The rail network doesn't grind to a halt with fog but it does slow down, its one of the various causes of the massive annual delays seen in winter and leaf fall season.
If a guard cannot see a signal and no indicator is provided then they are expected to get into a position where they can see them. In short, walk along the platform until its visible. In theory a call can be made to the controlling signaller but I believe the signaller cannot say the signal is off but that it is "set in your favour" or words to that effect.
The rail network doesn't grind to a halt with fog but it does slow down, its one of the various causes of the massive annual delays seen in winter and leaf fall season.
OFF indicators are specifically for staff despatching trains, banner repeaters for signal sighting where visibility is permanently restricted. Neither is specifically fog related.
Time was, with oil-lit signalling, no AWS, and heavy air pollution, that fog had a major impact on punctuality. I'm old enough to remember published Fog Service timetables, and being walked home through the last London smog....
Time was, with oil-lit signalling, no AWS, and heavy air pollution, that fog had a major impact on punctuality. I'm old enough to remember published Fog Service timetables, and being walked home through the last London smog....
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SemaphoreSam
Member
Is it in the near, or far, future, that signal indications will be readable on the footplate, without looking out windows? I think it's on some equipment now, but will it become universal? If so, will lineside signaling disappear eventually? Weather considerations would be lessened, and huge signaling cost savings would be realized, no? Sam
Matt Taylor
Established Member
Portsmouth Harbour has three banner repeaters each on platforms 3-5 with two provided on platform 1, this is due to the curvature of the station with no off indicators provided at all. Likewise platform 11 at Clapham Junction has a banner repeater but no off indicator. Banner repeaters are for guards and platform staff as much drivers.
I can think of two places where banners are used by platform staff and guards instead of OFF indicators and or directly viewing the signal. Those being Liverpool Street and Acle.
dk1
Veteran Member
I can always give you 2 on the buzzer first. The Acle banner can be very difficult to spot
short answer: it's done now, it will become more common, they will theoretically disappear, money MAY be saved.
Indeed, I think though the difference is that "OFF" indicators cannot be used by drivers to assume the signal is clear whereas banner repeaters can.
Railsigns
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It's likely to be a very long wait for an amber signal. They don't exist on the railway. A yellow one, on the other hand...
edwin_m
Veteran Member
ERTMS equipment is in use on the Cambrian line, and is supposed to appear on the Great Western and East Coast main lines over the next decade or so. There aren't really signals as such, instead the driver has a display indicating the safe speed and the brakes go on if it isn't obeyed.
Take a look here at forum member Railsigns' site: http://www.railsigns.uk/photos/p_traindis1/p_traindis1.html
(and, before anyone asks, yes some locations could have a routeing onto line 'F')
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As far as I am aware the off indicator also lights for subsidiary aspects for example if the main aspect is red but the position lights are lit to shunt into sidings or something .
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 .
All the off indicator is for is to tell the staff dispatching the train that the signal is in an aspect at which the train can proceed past it . Depending on the aspect the driver then proceeds accordingly .
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I can always give you 2 on the buzzer first. The Acle banner can be very difficult to spot
This , although not an official method of working . The effect is the same . The guard is made aware the signal is displaying a proceed asoect . The driver is aware that the signal is not ON
Railsigns
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Nobody viewing this forum will be able to see the hotlinked image in post #13 (unless it was already present in their internet cache), because I have taken measures to discourage hotlinking. All they will see instead is an annoying flashing warning notice.
moggie
Member
OFF indicators show OFF when the signal is controlled to a proceed aspect including a PL aspect if provided. Indeed they are primarily provided for staff carrying out train despatch duties from a position where the platform starter signal might often be unsighted by either platform buildings or the train which is being despatched. As such their sighting performance is low as they only ever need to be viewed over short distances. So typically this may be left hand positioned signals on right hand side platforms, but there are other scenarios.
Banner signals have much better sighting characteristics for their primarily purpose to aid the driver where the main signal sighting is constrained and therefore need to be viewed over greater distances to be of any use. If the position of the banner coincides with a platform which might otherwise require OFF indicators to aid train despatch then the Banner will suffice instead.
Banner signals have much better sighting characteristics for their primarily purpose to aid the driver where the main signal sighting is constrained and therefore need to be viewed over greater distances to be of any use. If the position of the banner coincides with a platform which might otherwise require OFF indicators to aid train despatch then the Banner will suffice instead.
I think we noticed that from Yorkies post. I still have the spots in my eyes.
Seriously though, have you considered the possibilty that such rapid flashing might affect someone epileptic?
carriageline
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I know of a location where a double sided OFF indicator is used on a running line, which repeats a semaphore signal. Prize for whoever can tell me where (presuming there isn't many around!)
PS it's not on a platform lol
(presuming there isn't many around!)PS it's not on a platform lol
Railsigns
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I think we noticed that from Yorkies post. I still have the spots in my eyes.
Seriously though, have you considered the possibilty that such rapid flashing might affect someone epileptic?
No, I hadn't, but it's a fair point. I can alter the flashing rate. Some adverts I've seen on certain websites are even worse, mind.
Searle
Established Member
21C101:1883024 said:
I think we noticed that from Yorkies post. I still have the spots in my eyes.
Seriously though, have you considered the possibilty that such rapid flashing might affect someone epileptic?
That was my thought as well, made my room temporarily into a club with all the flashing x_x
The guard will contact the driver and not the signal box, because if the driver cannot see the signal they would not take the word of the guard that the signal is off Fog will only cause minor delays as drivers can drive at linespeed in fog and know where everything is under poor visibility conditions, leaf fall is probably the highest annual cause of delay throughout the whole year.
Really!
So I have been doing it wrong all these years because I drive the same speed in fog as I do in any other weather conditions*!
*Freezing conditions likely to effect traction/braking excepted!
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:
I would dispute the most part (for now) but will concede that's changing! Still plenty of them about all over the place. I sign quite a few hundred miles of railway as a guard and they're still all over the place around here. Not many of my routes are semaphore/AB free so they certainly figure in my mind more than your own I guess.
All that stuff about double blocking has gone from the latest issue of the comic anyway! The only time I've really noticed fog causing a delay is when a train's missed the distant and the home signal is a semaphore that's not particularly visible.
There're still quite a few semaphores left up here in Scotland, and not just on branch lines.
Harbon 1
Member
And in the midlands, quite a lot in fact
Minilad
Established Member
Worcester. Arrrrrggggghhhhh!!
Fog shouldn't really slow anything down. Not if you have a driver up front who knows his road. Thats what we are paid to do
Fog shouldn't really slow anything down. Not if you have a driver up front who knows his road. Thats what we are paid to do
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