Ground Signals - Where are they used?

[3Valve]

Now I know we've got some retired and active signalmen on this here forum and I could do with some info on Ground signals.

I've got a few ground signals that I bought from Steve at Back2Bay6 a couple of years back but in all honesty I really have no clue about signalling at all.

Could someone with infinately more knowledge than me educate me in the use of ground signals please, so I have some idea where to put mine.

cheers

 

[don9GLC]

Could someone with infinately more knowledge than me educate me in the use of ground signals please, so I have some idea where to put mine.

cheers

I was never a signalman but you might find this helpful

http://en.wikipedia.org/wiki/British_railway_signals


I only ever came across the red-white / white-white aspects around the Glasgow Suburban Electrics.

Before electrification (and color light signals) the usual shunting signal was a white disk with horizontal red band (for red-white = stop). The disk would be rotated clockwise about 30 degrees for proceed (white-white) similar to the 'upper quadrant' semaphore main signals.

Essentially these signals allowed a locomotive or multiple unit to enter a block section that was already occupied, hence they would be found typically at carriage sidings or at the approach to terminus station platforms.

Hope this helps,

Don

 

[3Valve]

Thanks Don

Forgot to mention that it is the red/white disk type ground signals that I have, in case that makes any difference.

 

[don9GLC]

Thanks Don

Forgot to mention that it is the red/white disk type ground signals that I have, in case that makes any difference.

No. The red and white disks were replaced by the light signals. This link may be better for you

http://www.signalbox.org/signals/semaphore4.htm


Don

 

[3Valve]

Nice one don. Thanks for the link.

 

[Round n Round]

Hi Gareth

32 years in to job before they retired /(disposed of) me.

Happy to offer advice but could you send me a track plan then I can suggest some locations for your ground signals.

Cheers, Trevor.

 

[whatlep]

(snip)Could someone with infinately more knowledge than me educate me in the use of ground signals please, so I have some idea where to put mine.
(snip)

Basic answer is to provide a signalled manoeuvre that is not otherwise provided for by main stop signals (e.g. semaphore homes) on "running lines" (think main movements). So you need to provide a diagram and think about which routes would require "running" signals and which would not.

You may find this site helpful: http://www.signalbox.org/

You could use the ground discs for any of the following purposes:
1) Calling-on: admitting a train into a section of line already occupied by a previous train (usually at a station)
2) Shunt-ahead: what it sounds like, but with inherent implications about block working
3) Warning: line is clear only as far as the next stop signal (again associated with specific types of block working)
4) Shunting

Item (4) is probably most likely for most G-scalers, so I'll quote directly from the BR 1972 Rule Book (clause C.3.2.4 if you care!):
"Shunting signals govern the passage of a train from a siding to a running line, from a running line to a siding, between one running line and another, and control shunting operations." "When cleared, shunting signals authorise Drivers to proceed as far as the line is clear".

In case the last sentence doesn't sound logical, normally in the UK a cleared stop signal indicates the line is clear to the next stop signal with no obstructions possibly in the way. A driver passing a cleared shunting signal MUST expect the possibility of an obstruction before the next stop signal.

End of lesson! PM me if your brain needs more serious frying or just for an opinion on where you need main/shunting signals! :callme:

 

[3Valve]

Brain sufficiently fried thanks Peter.

Track plan as requested Trevor.

 

[flyingsignalman]

(snip)You could use the ground discs for any of the following purposes:
1) Calling-on: admitting a train into a section of line already occupied by a previous train (usually at a station)
2) Shunt-ahead: what it sounds like, but with inherent implications about block working
3) Warning: line is clear only as far as the next stop signal (again associated with specific types of block working)
4) Shunting

In the instances mentioned above a subsidiary signal (in the form of a miniature semaphore signal under the main arm) would normally be provided rather than a disc signal.

You could site a ground disc at either end of the station loop. Another could be placed leading from the sidings at the station reading to the main lines.

 

[whatlep]

Bearing in mind your track plan Gareth, this diagram of the signalling at Highley (Severn Valley) may be helpful:
http://www.svrsig.org/svr/Frame6.htm

To go into a bit of detail.....

(snip)You could use the ground discs for any of the following purposes:
1) Calling-on: 2) Shunt-ahead: 3) Warning: 4) Shunting
(snippety snip)

In the instances mentioned above a subsidiary signal (in the form of a miniature semaphore signal under the main arm) would normally be provided rather than a disc signal.
(snip)

Generally true, I agree, for items 1-3 which are indeed subsidiary signals, but there is nothing in the rules to prevent them being a disc signal. See examples from UK railways here: http://www.railsigns.co.uk/sect4page2/sect4page2.html .

Even today you can visit Worcester Shrub Hill and see a large shunting disc used as a main signal with a conventionally sized disc beneath it labelled as a calling on signal. As ever, there is a prototype for everything. See http://anoraksia.ukgeeks.co.uk/c717174.html

Item 4 would normally be a ground disc as it is distinct from a subsidiary signal, but equally there were plenty of examples of miniature arms. See same links.

 

[C&S]

Just for the sake of completeness - the Southern Region had a variant of a small lower-quadrant semaphore arm on a ground-level post, this was yellow with a black vertical stripe. Sometimes a similarly coloured disc was used, although this had a horizontal stripe. At one location known to me, the exit to Feltham yard in SW London, it was a full-sized signal. I think they showed either amber or green at night.

I believe that unlike a red/white ground signals that could not be passed when set to Danger, these were used at the exit to a set of sidings, where there was a headshunt that extended beyond the signal. When OFF the signal gave clearance to enter the main line, when ON it could be passed to run into the headshunt.

 

[Walts-Playmobil]

The ground signal with yellow and white lights is still in use. It may be used when there is a shutting neck. The train can pass it into the shutting neck any time. If however the train is going into the main line the points will be pulled over and the signal cleared for the train to proceed. This is to save the signal man having to clear the signal every time the train is required to go into the shutting neck.
There was also a full size signal with a square end (same as a home signal) that was painted yellow with a black strip. That saved the same purpose.

 

[Woderwick]

Oh this is an old pic of LBSCR rotating signsls for your interest

 

[whatlep]

(snip)I believe that unlike a red/white ground signals that could not be passed when set to Danger, these were used at the exit to a set of sidings, where there was a headshunt that extended beyond the signal. When OFF the signal gave clearance to enter the main line, when ON it could be passed to run into the headshunt.

Yep, that's the general idea. Technically, a yellow shunting signal can be passed when not clear for any movement "in a direction for which the signal, when cleared, does not apply" (BR 1972 Rule Book C 3.2.4 if anyone cares!). There were colour light examples of "yellow discs" too. They were usually used where moves within a yard needed to be made over points which led to a running line and having to signal every move would be a distraction the signalman. Popular with the bean counters since each signal operated added to a signalbox's 'lever pull' count which affected the box/ payment grade. Yellow disc= few pulls!

On the other hand, the Byzantine rule wording with its requirement for clear understanding on all drivers' parts about which routes were which and the general undesirability of passing a signal at danger made yellow discs extremely unpopular with the operating department! In some places, yellow discs were replaced by multiple red (standard) shunt discs so that the driver received a positive indication that he was OK to proceed. To appease the bean counters, there was usually an instruction that the red discs for moves within the yard could normally be left at 'clear' unless required to be set to danger - a reversal of normal signalling practice.

Here's some discs at the former Ordsall Lane No.4 box just west of Manchester. Yellow disc on the left, two red discs (which could also have been a yellow disc) on the right.

 

[PaulRhB]

Bear in mind this is a little over the top for most narrow gauge lines so you could easily lose the distant signals if line speeds are low. The taller of the two arms on the bracket signals indicates the main route, (usually the straighter one).
All signals are on the left as main line practice but if your drivers are on the right then so would your signals if they want good visibility.

 

[whatlep]

Bear in mind this is a little over the top for most narrow gauge lines so you could easily lose the distant signals if line speeds are low. (snip)

Yes, that would do nicely, though the red disc at the left hand end of the left hand station is unnecessary. Do we assume that the siding bottom left is operated off a ground frame and hence unsignalled? If not, that needs exit/entry signals too. Similarly for the engine shed road and associated siding on which a yellow disc could be placed (facing the shed).

Fun, ain't it!

 

[PaulRhB]

though the red disc at the left hand end of the left hand station is unnecessary.

The left end disc should really be a calling on but there are a few examples of a disc being used. I put it in to allow more shunt moves onto a train.

Similarly for the engine shed road and associated siding on which a yellow disc could be placed (facing the shed).

I assumed the two sidings and Loco shed were handpoints within the yard. Just the one dummy to control the exit for all three.

Do we assume that the siding bottom left is operated off a ground frame and hence unsignalled?

I would as it's probably a industrial siding and too remote to the nearest box to be fully signalled.

Need a Signalbox at each station too.

 

[New Haven Neil]

I'm interested to see the white with yellow stripe disc signals - I have a genuine 12 inch to the foot black with yellow stripe disc, is that the same thing? It's ex-north eastern region, if it's a regional variation?

 

[New Haven Neil]

Yes, it's one of those Gordon! Brand new, never been used. It was a gift many moons ago from an S&T man at Bishop Auckland together with a normal coloured one which is distinctly used!

 

[whatlep]

Some railways used a floodlit disc rather than one with a red or yellow stripe.

(snip)

Nice example of an LT calling on signal!

To answer an earlier post, the yellow bar on a black disc is exactly the same as yellow bar on white disc in terms of purpose. It was intended for use where the signal would be floodlit, rather than backlit. Black background colour was used so the yellow band would appear more clearly at night under the floodlight. See here for more: http://www.railsigns.co.uk/sect3page4/sect3page4.html