GWR Signals and where they go?

[dantimmy]

 

Updated. I think I will properly use a ground disc to control the exit from the sidings.

[PWSlack]

....distant signals were fixed at danger on lots of branches which saves having to operate them ....

They are fixed at danger because there is no scope to operate them at passing loops and terminus stations.

[beast66606]

They are fixed at danger because there is no scope to operate them at passing loops and terminus stations.

 

Birkenhead Woodside, a terminus, had a workable distant, which was even continued with the BR box, which was a 1950s replacement for the Saxby structure.

For a long time colour lights showed green to the bufffers at terminals, which is equivalent to a workable distant.

Scottish single lines had passing loops with working distants.

 

The fixing at caution (or fastened to danger as the LNWR called it) was normally because the speed limit was 40mph or less, on most single lines this was the case because of tablet exchanges, but with automatic exchangers this could be raised, hence working distants.on some single track lines.

[The Stationmaster]

They are fixed at danger because there is no scope to operate them at passing loops and terminus stations.

Why not?

[Neal Ball]

Wow, an excellent thread which having been out of the country I have only just caught up with.

 

The advice from Mike (Stationmaster) is to top-notch and on the button - but we would not have expected anything less! - I know where I will be heading when it comes to paying down the signals for Wharncliffe Junction.

 

However, I have a quick observation - I would move the Goods shed from the back road, generally the back road would be free for vehicle access and the Goods shed, could go onto the road next to the Platform.

 

Hope that does not add to the confusion!

 

Regards,

Neal.

[micknich2003]

Not by any chance the Wharncliffe on the H&B and GC Joint line? Mick Nicholson.

[Budgie]

 

Updated. I think I will properly use a ground disc to control the exit from the sidings.

First of all the explanations from The Stationmaster have omitted the concept of Starting signals. What's the difference between a home signal and a starting signal? Usually, a home signal is passed by a train before the signalbox; a starting signal is passed after the signalbox. There are exceptions, usually when the signalbox is beyond the end of a station platform.

 

You have labelled the signals wrongly in your latest diagram: a is not the section signal, but the starting signal; b is the advanced starting signal (which is the section signal) with the distant for the next signalbox and shunt-ahead signal below it; c is the starting signal (also the section signal) and distant, and d is the home signal. These would be distinguished by being preceded by "Up" and "Down", being the descriptions of the lines they reefer to. You don't have a home signal on the road through platform 2. You also do not show the position of the signalbox on your diagram.

 

Here's a question for The Stationmaster: Have you come across a distant backing signal? (Yes, at least one did exist.)

Edited December 13, 2011 by Budgie

[dantimmy]

Wow, an excellent thread which having been out of the country I have only just caught up with.

 

The advice from Mike (Stationmaster) is to top-notch and on the button - but we would not have expected anything less! - I know where I will be heading when it comes to paying down the signals for Wharncliffe Junction.

 

However, I have a quick observation - I would move the Goods shed from the back road, generally the back road would be free for vehicle access and the Goods shed, could go onto the road next to the Platform.

 

Hope that does not add to the confusion!

 

Regards,

Neal.

 

I have been thinking about that, got to wait until next week (when i'm home) to see if i can make any changes

[beast66606]

First of all the explanations from The Stationmaster have omitted the concept of Starting signals. What's the difference between a home signal and a starting signal? Usually, a home signal is passed by a train before the signalbox; a starting signal is passed after the signalbox. There are exceptions, usually when the signalbox is beyond the end of a station platform.

 

Yes, there are plenty of exceptions but they are all stop signals. Starters (or advanced starters) are just names, usually for the section signal and I can see StationMaster has described that adequately.

 

You have labelled the signals wrongly in your latest diagram: a is not the section signal, but the starting signal; b is the advanced starting signal (which is the section signal) with the distant for the next signalbox and shunt-ahead signal below it; c is the starting signal (also the section signal) and distant, and d is the home signal. These would be distinguished by being preceded by "Up" and "Down", being the descriptions of the lines they reefer to. You don't have a home signal on the road through platform 2. You also do not show the position of the signalbox on your diagram.

 

I would suggest A is the home and B the starting - not sure if there is an advanced starting as it's not part of the area of interest. The road through platform 2 ? I assume you mean the siding ? that doesn't need a signal, if you mean the main line why does it need anything other than what's been drawn ?

 

Here's a question for The Stationmaster: Have you come across a distant backing signal? (Yes, at least one did exist.)

 

We know, we've done that

[The Stationmaster]

First of all the explanations from The Stationmaster have omitted the concept of Starting signals. What's the difference between a home signal and a starting signal? Usually, a home signal is passed by a train before the signalbox; a starting signal is passed after the signalbox. There are exceptions, usually when the signalbox is beyond the end of a station platform.

I have purposely avoided signal naming and concentrated on purpose - let's not run before we stroll eh? And of course in reality there is no difference in principle between Home and Starting Signals because they all carry out the same role - as stop signals; there is, of course, no such thing as a 'concept of Starting Signals', merely a naming convention (which differed between Companies and Regions) and it relates solely to their position relative to the signalbox.

 

You have labelled the signals wrongly in your latest diagram: a is not the section signal, but the starting signal; b is the advanced starting signal (which is the section signal) with the distant for the next signalbox and shunt-ahead signal below it; c is the starting signal (also the section signal) and distant, and d is the home signal. These would be distinguished by being preceded by "Up" and "Down", being the descriptions of the lines they reefer to. You don't have a home signal on the road through platform 2. You also do not show the position of the signalbox on your diagram.

So if he hasn't yet shown the position of the signalbox how on earth do we know what the signals are correctly called :scratchhead:Clearly the names of the Section Signals are in the wrong place but the sketch has been through several iterations and will no doubt be refined a bit more before we sort a few details like that - the big step is to get the signals in the right place and understand why it is done that way. Incidentally if the signalbox is logically sited nearest to the concentration of pointwork then signal a would of course be the Home Signal - and that is one reason why it is sensible to avoid the naming things on a part developed sketch.

 

Here's a question for The Stationmaster: Have you come across a distant backing signal? (Yes, at least one did exist.)

I know of one location where what at first sight might be described as a 'distant backing signal' once existed - I can't recall seeing it when I first visited that place in 1962 but that's hardly surprising as it was removed in February 1955 . But again we are looking here at the basics and usual principles and not at the esoteric, highly specialised, and extremely rare (possibly unique? - I have not yet come across anything to indicate there was another anywhere) in a signal which served a very particular purpose - and which, as it happens, was not even worked in accordance with the principles governing Distant Signals.

Edited December 14, 2011 by The Stationmaster

[The Stationmaster]

Right, alarums and excursions to one side and back on track we have finally got to what the GWR called 'disc signals' (or 'independent disc signals') and what the BR Rule Book calls 'shunting signals.. Pictures are worth a lot of words so we'll start with a pic of what we're going to look at - a fairly typical GWR ground disc signal, and as you can see it consists of a white disc background with a red bar across it. In the danger (or 'on') position this bar is horizontal and when the signal is 'off'/showing a proceed indication the red bar inclines at roughly 45 degrees - in the same lower quadrant as a semaphore arm.

 

 

The important thing to understand about this signal is that (while it is still a stop signal) because it is used for shunting movements it has a different meaning from running signals when it is 'off' and while it indicates that the route is set any driver of a movement passing the signal must be prepared to stop short at a handsignal or vehicles or other locos etc. In other words we have a very different principle from the one we encountered earlier with semaphore arm stop signals.

 

The GWR changed and refined its ground disc practice over the years moving first from points indicators (which moved in concert with points) to 'independent signals' so called because they were worked by their own lever independently of the lever which worked the points to adding a disc face to the miniature cast metal semaphore arms initially used on independent signals to subsequent designs of signal base which culminated in a new Western Region design shortly after nationalisation.

 

Some discs signals had more than one arm (the disc faces were still called 'arms') and this arrangement first appeared in the original miniature semaphore style which seem only to have have had a maximum of two arms. Between the World Wars disc signals appeared with as many as four arms (which seems to have been the GWR maximum from information unearthed to date) although that many was something of a rarity. Double discs were fairly common and triples could be found in a number of places. The original reason for adopting two arms was that the earlier designs of GWR interlocking in signal box lever frames only allowed the disc signal to be cleared when points were set in one direction - with the points set in the other direction the ground disc's lever was locked and the signal could not be cleared. The GWR got round this from the late 1880s onwards by altering many such discs to show a white light instead of red when at danger which allowed them to be passed in the 'on' position for some movements (under the control of aShunter). The alternative was to either use the signals with two discs - thus giving one for each route - or in more complex layouts to adopt us a Backing Signal with a mechanical route indicator for some movements. But adding arms of course meant extra signalbox levers = greater cost so such things were not too common at smaller stations.

 

By the interwar period new multiple arm discs signals were developed and the two pics below show a two arm disc in a rather unusual state - as it wasn't in use when the pics were taken in 2009 the enamelled red/white discs had not been bolted onto the arm castings. Incidentally this style of main upright casting was also used for three and four arm discs.

 

 

Where multiple arm discs (or indeed any signal with the arms arranged one above the other on the same post) are used there is a standard convention regarding their meaning - the uppermost arm reads to the route furthest to the left and the lowest arm reads to the route furthest to the right; it doesn't matter whether one route is straight and the others are divergences or if one route is more important than the others the convention remains the same for arms of equal importance, top to bottom (arms) = left to right (routes).

 

The GWR got quite heavily into multiple arm discs in the 1930s but post-war was back to not only using single arms in some new work but even using discs that only read one way through points. This meant that even in the 1970s we were still using handsignals to get moves past such discs. However later work saw discs reading both ways (where necessary) at points.

 

There are some other areas we have yet to cover such as 'STOP' boards and we'll also have a look at Goods Line signalling although it doesn't involve Dantimmy's layout ideas (which will also be looked at as his ideas firm up from what he has hopefully picked up from my notes so far. In the meanwhile I shall have to be spending a bit of time back writing up stuff for the 12':1ft railway.

[Neal Ball]

Not by any chance the Wharncliffe on the H&B and GC Joint line? Mick Nicholson.

 

No very much Thames Valley GWR!

[The Stationmaster]

D**@! it - just lost half a page of the next bit for some reason. I shall have to redo it in Wurd or some such and copy it over as RMWeb (or AOL - of course, probably AOL) seems to be playing some of its tricks again. Alas it probably won't now come forth until tomorrow having totally lost my train of thought.

[The Stationmaster]

And for the second attempt Ill look first at 'boards' - not as in the slang name for signal arms but in the descriptive of 'Limit Of Shunt' (LoS) and 'STOP' boards. These are in many respects direct equivalents of signals but they can only show one indication and they are not connected to a signalbox.

 

The simpler of the two to understand is the 'Limit Of Shunt' board which appeared on the GWR sometime between the early 1920s and early-mid 30s and was constructed in a fairly distinctive way that made it unmistakable when compared with the styles used by other Companies. The face of the board was glazed in a white translucent glass on which the lettering was painted in red. Regrettably I haven't got a scanned view of an LoS board but a good illustration of the face of the board can be found here http://www.railsigns...sect5page1.html at item 5.3 and as can be the sign was square (but I haven't got a dimension, and can't find one anywhere at present). The sign was back illuminated with a tapered square 'funnel' which reduced the size down from the square front of the sign to fit it in front of a standard signal lampcase, later version in colour light signalled areas were usually electrically lit.

 

As its name implies the LoS board was used to mark the limit to which a shunt movement could proceed but it needs to be understood that this applied to movements in the wrong direction, i.e. contrary to the normal direction of running on the line concerned. Thus you would never find an LoS facing oncoming trains running in the right direction over a line, which apart from anything else meant they would not be found on a single line. Thus they could be found where trains set back during shunting movements and they might lie within Station Limits or they might be back into the block section - but only for the minimum necessary distance - or there might not be an LoS and movements would be limited by a ground disc signal reading through a crossover or to a siding. And of course prior to them being provided - and they rarely appeared at ordinary wayside stations - the movement would simply be stopped by a Shunter or Guard giving a handsignal to the Driver.

 

The GWR 'STOP' board was equally distinctive in appearance, again illustrated on the Railsigns site as I've no scanned pic of one (or any dimensions, alas) http://www.railsigns.co.uk/sect20page1/sect20page1.html at item 20.8. This sign was backlit in a similar manner to the LoS but in this case the taper was only from the top and bottom and the sides remained parallel because it was much narrower. While the board has a very obvious meaning its use was rather more complex than that of an LoS and basically it was used to halt a movement where there might not be a person on the ground able to give a handsignal to stop it. A very good example of this is a yard reception line where the Signalman would let a train in off the running line (in a facing direction) and the train would proceed to the STOP board to await a handsignal or instructions from the yard staff. Similarly the boards could be used where different sections of a yard converged allowing the Shunter or Foreman in charge of each section to despatch a train towards the board without bothering whoever was in charge of the section beyond it. The key thing to remember is that that these boards were originally used in busy locations although in BR times they could be found on freight only branches where there were no other signals except handsignals.

 

A simple way of distinguishing between the two in some respects is that a Limit of Shunt almost invariably applied to a train going in the wrong direction on a running line while a STOP board applied to one going in the right direction.

 

Now to Goods Lines and a bit of thinking back to the terminology and concepts we came across when looking at stop signals. The principle we came across then was that only one train was allowed in a Block Section at a time (in normal working) and equally only one train was allowed in a Signal Section. Now we're going to stand that idea on its head and break that basic rule. On a Goods Line a different method of block signalling called Permissive Block was used and as the name suggests things were a bit more lax - in fact so lax that we could have more than one train at a time in a Permissive block section. In fact so lax that Signalmen could allow as many trains as it would hold into such a section (the most I have ever seen at once is 5 trains). On the GW goods lines used the special arm with a ring (which we have already seen) and after these were abolished for new work a shorter (3ft) version of the standard arm was used. Just to be contrary the GWR didn't necessarily name all its permissive lines as 'Goods Lines' - for example in the Cardiff Valleys there were Main and Relief Lines and the Relief Lines were worked Goods Permissive. But at, for example, Reading the Relief Lines were Absolute Block (like the Main Lines) and the Goods Lines were Goods Permissive. How do you tell which was what - alas you have to research the area concerned, there was no hard & fast naming convention.

 

Now we'll go back to something else we came across earlier - the Calling On Signal which - you'll remember was used to control a movement into an occupied Signal Section. But one place where it wasn't used in that way was on a Goods Line. In this instance the way in which a signal was lowered (after he had reduced speed and was slowing to stop at it) indicated to a Driver that the section ahead was occupied by another train. And before anyone asks there was always a debate of interpretation regarding Signal Sections in Station Limits on Goods Permissive Lines with one school saying such Signal Sections were permissive and the other saying they weren't. In one Division I worked in our Divisional Chief Signalling Inspector would have shot any of us who said they were but in the Division next door there was a slightly more relaxed view. In later years when the interpretation was down to me for the whole Region I took the view that they must be permissive - but that of course was well into BR days.

 

I'll now post this before doing some editing to add a few pics which are vaguely related to this piece but also refer back through to other things.

[The Stationmaster]

I'm putting the pics in a separate post because they don't all relate to the last subject area. Firstly a once common GWR answer to restricted clearance siting - the centre pivot arm. There are still a few survivors - Liskeard Up Inner Home has appeared recently on RMWeb while I presume the Shrewsbury ones (which are mounted upside down ) are still there as are the splitters at Droitwich Spa. Here is an example at Didcot GWS in all its restored splendour

 

 

and here is one from the past, complete with a mechanical stencil route indicator, applying to Platform 6 at Reading

 

 

And also at Didcot GWS is this excellent array beautifully illustrating a number of things. Reading from left we have a pretty ordinary stop signal but it boasts an unmistakable subsidary Shunt Ahead arm and on a small bracket to the right of the main post a much rarer sight of a 'to Goods Line or Siding' arm - also centre pivot but smaller than the examples seen above and in this case not carrying a white stripe but instead having the ironwork of the pivot painted white (a fairly old practice which was discontinued in later years.

Next to the right we see the back of a stop signal complete with a Sighting Board - on the important side these were painted white and intended to give a contrasting background to make the signal arm more visible, they were used on both stop and distant signals. The alternative - if there was bridge etc handy was to paint a white patch on something behind the signal and examples of that are still to be seen over 40 years after the signal they served has gone.

Finally over in the right distance we can see the back of the centre pivot signal.

 

 

Finally an example of underslung arms just to show that not only did the GWR go in for them but that the WR came along and put in replacenets in nice modern tubular steel with enamelled arms. Sorry it's not the best pic in the world (probably nearer the 'worst' end alas) but still a comparatively rare sight of a splitting signal, here in the form of Goring's Up Main Home Signal.

 

[The Stationmaster]

Having got through most of what dantimmy started me off with I wonder if any of those who have expressed an interest in this subject would like me to expand it a bit to look at such things as, say, junction signalling and single lines - ideally continuing it in a GWR vein (unless someone would liek to see it widened)?

[figworthy]

Having got through most of what dantimmy started me off with I wonder if any of those who have expressed an interest in this subject would like me to expand it a bit to look at such things as, say, junction signalling and single lines - ideally continuing it in a GWR vein (unless someone would liek to see it widened)?

 

Can I make a late expression of interest, and say "Yes please" ?

 

 

Adrian

[rovex]

Again - please carry on. I've found this thread very interesting and easy to follow unlike a lot of signalling explanations. Could Andy perhaps be persuaded to edit it together as an article in the RM Web online mag??

[Budgie]

Can I make a late expression of interest, and say "Yes please" ?

Me too. In my experience, I think I know it all, when really I know next to nothing.

[Happy Hippo]

Having got through most of what dantimmy started me off with I wonder if any of those who have expressed an interest in this subject would like me to expand it a bit to look at such things as, say, junction signalling and single lines - ideally continuing it in a GWR vein (unless someone would liek to see it widened)?

Mike,

 

I think it best that you flesh out what you have started and call it a book! At least you might get a little return on all your efforts for us on RM Web.

 

A second volume on ground signals, 'Dummies for Dummies' would be a natural successor.

 

Regards

 

Richard

[The Stationmaster]

Mike,

 

I think it best that you flesh out what you have started and call it a book! At least you might get a little return on all your efforts for us on RM Web.

 

A second volume on ground signals, 'Dummies for Dummies' would be a natural successor.

 

Regards

 

Richard

Thanks for that Richard - actually some of it is distilled (fancy word for nicked) from 'the book' although the master (only?) copy is currently with 'a friend in the north' for his views to be expressed and as it was written in the early '90s and I have learnt a lot since then it does need some re-working. But yes I will be trying to have a chat with the very patient publisher in the coming year to see if something can be done. I've also got getting on for 1,000 photos to supply the necessary information - heavily edited down of course - to illustrate it having dashed around a fair part of Britain over a couple of years to capture most of the necessary (that sounds worse than it is as the only place you could, for instance, get a picture of an SCR colour light signal numberplate was in, hmm, Scotland .. and so on - yes, it also includes colour lights as well and a lot of Principles have changed since I wrote it all).

[Neal Ball]

Thanks for that Richard - actually some of it is distilled (fancy word for nicked) from 'the book' although the master (only?) copy is currently with 'a friend in the north' for his views to be expressed and as it was written in the early '90s and I have learnt a lot since then it does need some re-working. But yes I will be trying to have a chat with the very patient publisher in the coming year to see if something can be done. I've also got getting on for 1,000 photos to supply the necessary information - heavily edited down of course - to illustrate it having dashed around a fair part of Britain over a couple of years to capture most of the necessary (that sounds worse than it is as the only place you could, for instance, get a picture of an SCR colour light signal numberplate was in, hmm, Scotland .. and so on - yes, it also includes colour lights as well and a lot of Principles have changed since I wrote it all).

 

Mike this sounds very interesting. I have always relied on the Adrian Vaughan book "A pictorial record of Great Western Signalling" published 1973 for £3.60 !!

 

Your advice in this thread has been fascinating and I am sure (having seen a few of your 'photos) that the stock of 1000 will be a great treasure trove.

 

Looking forward to the book Mike.

[The Stationmaster]

 

Mike this sounds very interesting. I have always relied on the Adrian Vaughan book "A pictorial record of Great Western Signalling" published 1973 for £3.60 !!

Your advice in this thread has been fascinating and I am sure (having seen a few of your 'photos) that the stock of 1000 will be a great treasure trove.

Looking forward to the book Mike.

Fingers crossed then - although it's still 'in the north' (and it's not just GW/Western - the pic taking expeditions ranged from West Cornwall to the East Coast, North Wales coast, and as far north as Perth plus a day on the Barley Mow as some Southern folk are inclined to call a certain route). BTW over recent days I've been delving through some of my pics saved on disc which are mainly recent but include some scans of 1960s stuff and will be adding a few to this thread when we have a re-established upload facility; I tried an upload on another thread last night and no joy so I'll wait 'til Andy give the all clear.

[Neal Ball]

Fingers crossed then - although it's still 'in the north' (and it's not just GW/Western - the pic taking expeditions ranged from West Cornwall to the East Coast, North Wales coast, and as far north as Perth plus a day on the Barley Mow as some Southern folk are inclined to call a certain route). BTW over recent days I've been delving through some of my pics saved on disc which are mainly recent but include some scans of 1960s stuff and will be adding a few to this thread when we have a re-established upload facility; I tried an upload on another thread last night and no joy so I'll wait 'til Andy give the all clear.

 

At one time I had a load of slides showing the signals at Newton Abbott, taken in the 1970's - sadly now lost through the passage of time and several house moves.

[The Stationmaster]

 

At one time I had a load of slides showing the signals at Newton Abbott, taken in the 1970's - sadly now lost through the passage of time and several house moves.

Really must find mine sometime!! I do however have a postcard showing new signals at the east end of Newton Abbott platforms in the 1920s,one of the best I have ever found for signal views.