Welcome to this specialist bit of the Forum.

Deciding where to put signals on a model railway is difficult, mainly because the distances are so compressed that Distant signals, for example, would often be well off the scene.

I would recommend visiting John Hinson's web-site on signalling matters www.signalbox.org which gives a straightforward description of the British signalling system.
For books I'd suggest "Railway Signalling and Track Plans" by Bob Essery, published by Ian Allan in 2007, ISBN 978 07110 32156. This describes how the prototype did it with some comments at the end about interpreting it into model form.

If you want to post track plans here a couple of us will try and suggest where you might put signals (on the layout, that is!).

Regards,
John Webb

 

Other useful websites for signalling are http://www.railsigns.co.uk/home.html and http://www.railway-technical.com/sig-uktypes.shtml

 

Capt, please post up your track plans cause if it's signalling you're after it's signalling you're gunna get mate!

 

QUOTE (Lancashire Fusilier @ 21 Oct 2008, 03:34) <{POST_SNAPBACK}>Capt, please post up your track plans cause if it's signalling you're after it's signalling you're gunna get mate!

That's very kind of you

Cheers
Cpt Jack

 

Can we conclude that signals are to give train drivers instructions about the state of the line ahead?

So if there is a junction, point, crossing, siding, station or stopped train up ahead then a signal will be in place to protect the line where the problem could occur.

A stop signal (home?) is where the train must stop, and a distant signal is located at the point where the train must start breaking so that it can stop in time at the stop signal if the stop signal is in the 'stop' position.

Is this right?

I want signals to tell me the state of the layout so I can walk around and drive the trains. I don't want to have to look back at the control panel to see if the points ahead of me are set for or against me.

I really hope that Hornby, Bachmann or another large company can produce a range of semaphore signals that are ready and easy to use as well as being reasonably priced.

 

Doug, everything you say makes sense.

Capt. What era is your layout set in? I am assuming some sort of semaphore signalling would be what you want, as accurate as is practical with considerations that distant signalling on most modest layouts is not really practical due to the length of the block section and as a compromise having a fixed distant on a home signal is sensible.

If it is coloured light then it is a different approach.

I would suggest too that your layout could benefit from another signal box, perhaps near the goods shed on the lower level.

If you haven't already have a look at my thread on my layout here signalling as there are some similarities present.

 

QUOTE (Lancashire Fusilier @ 21 Oct 2008, 12:17) <{POST_SNAPBACK}>Doug, everything you say makes sense.

Capt. What era is your layout set in? I am assuming some sort of semaphore signalling would be what you want, as accurate as is practical with considerations that distant signalling on most modest layouts is not really practical due to the length of the block section and as a compromise having a fixed distant on a home signal is sensible.

If it is coloured light then it is a different approach.

I would suggest too that your layout could benefit from another signal box, perhaps near the goods shed on the lower level.

If you haven't already have a look at my thread on my layout here signalling as there are some similarities present.

Hi there, set in the early sixties, and yes semiphor is th style I want, I have since built a second signal box and it's ready to go in location.

Cpt Jack

 

Cpt, did you ever post your layout? I can't recall actually seeing it.

 

I did, 4 posts above this one.

Cpt Jack

 

Sorry, I was going to take a look at it back in October but other family things got in the way and drove it right out of my mind. I'll try and do something by the end of the month.

Regards,
John Webb

 

Hi Cap'n.

Just found your thread which I must have missed first time around.

I too have been looking at signalling for my layout, which, incidentally, bears a striking resemblance to your own. However, the more research I do, the more confused I get.

I think I have cracked the 'Home' v 'Distant' issue but the difference between Upper and Lower Quadrants is totally eluding me. Common sense would suggest that upper quadrant signals should be taller than lower quadrant but, having looked at countless pictures, I find that this is most definitely not the case as I've found pictures of lower quadrant signals which are taller than upper quadrant and vice versa.

As I am modelling GWR I am aware that GWR used lower quadrant only and I would therefore not wish to have an upper quadrant signal by mistake.

If anyone else reading this thread can enlighten me I would be very grateful. Incidentally a diagram of my layout can be found in my 'Model of the Model' photo album if that is any help.

 

The GWR (and subsequently the WR of BR) always used lower quadrant signals, as indeed did other companies, for example the Midland Railway. But as I understand it, the lower quadrant arms needed heavy cast 'spectacles' (the bit with the coloured glass in) to ensure that that end of the arm was the heaviest so that signals automatically returned to the horizontal 'danger' position if any connection between the arm and the bits at the bottom of the signal post broke.

As signals developed, the upper quadrant became favoured as the arm and the spectacles could be made from lighter and thinner metalwork, yet the arm would still return to horizontal if the connections broke. But with the lighter and cheaper metalwork the signals were less costly to make and easier to maintain.

All signals, upper or lower quadrant, were sited at a height where the driver and fireman had the best view on approaching them. The various railway companies also had different driving positions for various historic reasons, and the GWR locos were all driven from the right-hand side. So the signals on the GWR had to be placed where the driver on the RHS of the loco could see them.
But railways are crossed by bridges and at stations there are buildings and canopies which may obstruct the view of signals. So the signals may have to be placed at different heights to give the best view. Even today with colour-light signals they still have to have 'Sighting Committees' when resignalling is taking place to ensure that the signals are placed where the drivers of all sorts of trains have the best view.

Take a look at www.signalbox.org which has a comprehensive history of British signalling and many examples of signals and signal boxes from pre-grouping to BR.

Hope the above helps,

Regards,
John Webb

 

Hi John,

Thanks for the potted history but it still doesn't answer the question. What exactly is the difference between Upper and Lower Quadrant signals? Is it just the way they were made ?

 

QUOTE What exactly is the difference between Upper and Lower Quadrant signals? Is it just the way they were made ?

Consider a signal at danger. The arm is in the horizontal position.

• When a lower quadrant signal is cleared, it drops to the lower quadrant of an imaginary circle with its centre at the pivot point of the arm.
• When an upper quadrant signal is cleared, it is raised to the upper quadrant of the same imaginary circle.

As John has already stated, a signal should fail to the danger position.

• A lower quadrant signal, there must be a heavier counter balance to pull the arm back horizontal position.
• An upper quadrant signal can fall back under its own weight

There is another significant difference in appearance between the two signal types.

• The spectacle plate (the Red and Blue/Green) filters of a lower quadrant signal are arranged vertically. This gives the signal an overall "J" shape.
• The spectacle plate filters of an upper quadrant signal are arranged horizontally. This means the signal arm is little more than a bar.

I hope this helps

David

 

Trevor - sorry I didn't make clear the difference. The website I gave you above has much better diagrams and pictures than I could give you, so take a look at that for the detailed information.

And if you wondered why David (dwb) refers to 'Blue/Green' for one of the filters it's because the yellow light from the oil lamp behind the spectacles passing through a blue filter gives you a green light with minimum loss of intensity.

Regards,
John Webb

 

QUOTE (Cpt Jack Sparrow @ 3 Feb 2009, 16:10) <{POST_SNAPBACK}>I did, 4 posts above this one.

Sorry about then. My new work has something that prevents these images from being displayed and I can't see anything. Oh well, John is on the case and he is excellent and did several iterations of mine.

 

Thankyou gentlemen,this post is proving usefull to me also

 

QUOTE (dwb @ 4 Feb 2009, 00:47) <{POST_SNAPBACK}>I hope this helps

David

Thank you very much David for your very clear and concise response. I have not seen this difference clarified in any of the books or magazines I have read but now I understand it fully. It's so simple really.

Thanks again

 

Right, I've had a quick look at the plan and need to ask a few questions about parts of the Layout.

'Main Line Terminus'
Whats the purpose of the short line stopping short of the end of the lower platform?

'Branch Line Terminus'
Headshunt to Goods Shed - is this a platform face that could be used by a passenger train, or is there a wall or fence shutting off the line from the platform?
Likewise the line acting as a headshunt into the engine shed - is that also isolated from the platform?
(Just that if passenger trains are to use those tracks, the signalling requirements are more strict than if they are goods only.)

Regards,
John

 

Further to my explanation above, there are photos of each type in my photo albums. They're a bit large for inline posting so I've just posted links.

A photo of a gantry of lower quadrant signals on the Severn Valley Railway at Bridgenorth link

And here is a gantry of upper quadrant signals at Appleby on the Settle & Carlisle. You have to look at it carefully as I was more interested in the gantry construction rather than the arms themselves - link

David

 

Thanks for you time helping me with this

QUOTE (John Webb @ 4 Feb 2009, 12:55) <{POST_SNAPBACK}>Right, I've had a quick look at the plan and need to ask a few questions about parts of the Layout.

'Main Line Terminus'
Whats the purpose of the short line stopping short of the end of the lower platform?

John good spot on this one, I have actually not put that one in on the layout

QUOTE (John Webb @ 4 Feb 2009, 12:55) <{POST_SNAPBACK}>'Branch Line Terminus'
Headshunt to Goods Shed - is this a platform face that could be used by a passenger train, or is there a wall or fence shutting off the line from the platform?
Good only no passenger traffic

QUOTE (John Webb @ 4 Feb 2009, 12:55) <{POST_SNAPBACK}>Likewise the line acting as a headshunt into the engine shed - is that also isolated from the platform?
(Just that if passenger trains are to use those tracks, the signalling requirements are more strict than if they are goods only.)

Yes again isolated to passengers

Much aapreciated

Cpt Jack

 

All noted - be back in a few days with some ideas.

Regards,
John

 

Thanks John

I really do appreciate you help

Cpt Jack

 

Before I get down to the 'nitty-gritty' I'd like to explain that I'll be posting three diagrams:
1 - the Mainline terminus
2 - the Branch terminus
3 - the interconnecting lines.

I've done this to maximise the detail visible in each drawing. Each diagram will be in a separate post for easy quoting as needed, but do remember that comments on diagrams 1 & 2 are also related to diagram 3. And due to other things happening away from the computer tomorrow it may take me to Wednesday to get everything loaded up, so please can everybody hold on to the comments until it's all posted up?

The main line terminus (I've omitted the mainline under this terminus for clarity and some of the engine shed tracks which don't need signals.)

Sorry it's come out smaller than I thought it would.

I've lettered the signals. Their functions are as follows:
A - Branch 'Home' - protects the terminus from a train entering until the branch platform is clear.
B - Branch Starter - allows trains to leave the branch platform for the branch
C - Branch/Main line - allows train to leave the branch platform for the Main line.
D - Platform Starter - for the platform nearest the branch platform
E - Platform Starter - for the other platform
F - ground disc to give permission to exit goods/loco sidings
(Ideally there ought to be a trap point as indicated to protect the passenger lines against shunting runaways.)
G - Ground disc to allow engine to use the loco release cross-over
Home signals for trains approaching from the main line:
H - to Branch Platform
J - to main platform
K - to other platform
L - to Loco/goods roads - hence the small arm to indicate a move into a siding - which may be partly occupied.
M - Ground disc with stencil indicator allowing shunt moves into any of the various platforms or the loco/goods road. Two possible versions of the stencil indicator are shown, either varient may have been chosen for use on the prototype railway.

Originally the signals H to K would each have had a small arm below the main arm for 'Calling On' into occupied platforms, for example when a loco was running round its train. But all the extra arms meant more maintenance costs. So many of these were replaced by the single shunt disc with an indicator as I have shown.

The main arms can be used for shunt movements out of the three platforms, conditional upon something I'll explain in connection with diagram 3.

So here ends the first part!
John Webb

 

Part 2 - the Branch Terminus

A slightly easier layout than the Main line terminus.
I have assumed that there could be at least two trains active on the branch (two passenger or one passenger/one goods) - if the branch was 'One engine in steam' you could do away with everything except the signals for passenger trains (A,B,E,F) and rely on hand signals - but try modelling a signalman waving from his box....!

Signal Functions:
A - Home signal allowing trains to run in to the main platform
B - Home signal allowing trains into the other platform
C - Ground disc allowing movement into the goods shed headshunt
D - ditto allowing movement into the engine shed headshunt.
(There might need to be another disc or 'calling on' arms allowing a shunt movement into either platfom when occupied by a train, but it's not essential in my opinion and could easily be a hand-signalled move.)
E - Starter signal from main platform
F - Starter signal from the other platform

The unlabelled ground disc at the engine release crossover is to signal a loco across this, although on a branch line this could well be a crossover worked from a local ground frame and with no signals.

There are two ways of dealing with the sidings:
H - a 'Yellow' ground disc signal. Once a train is in the head-shunt it can move backwards and forwards past the signal at the horizontal 'Caution' position as it needs to for shunting the goods shed. When the loco/train needs to leave the head-shunt for the 'main' line, the crossover is operated and the disc moves to the clear position.
G1,G2 - 'Co-acting Ground Disc signals' - again once the loco or loco + vehicles is in the headshunt and 'locked in' by the crossover being normal, the two ground signals are cleared and shunting can go on as needed. For a train or loco to leave the siding, both are put to danger, the crossover reversed, and then only G2 cleared to signal the train to leave. Conversely if another loco arrives and needs to gain access to the loco shed, G1 and G2 are put to danger, thus stopping the shunting, the crossover reversed and the loco enters....

Trap points are not needed on the sidings as the crossovers perform this function.

So ends Part 2. Hopefully I will get part 3 posted tonight - but I've got to go out now.

Regards,
John