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Correct size signal box


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Sometimes when I look at a model railway the illusion is spoilt by a wrong sized signal box. It is either too big for the number of levers it should have or “How the hell did they get all those levers in such a small box?” Many times it is due to the modeller buying a ready to plonk or kit signal box that looks nice. That is Ok for those who do not wish to follow prototype practice that closely. For those who do here are my ideas to try and get a suitable sized signal box.

 

Most layouts start off with a track plan. On it we tend to place the important railway buildings, like the station and goods shed. Why not at this point put in the signalling. Some of us have enough knowledge to do this ourselves. You might be in the group that may not have this knowledge, there are many on this forum only too willing to help with signalling. Not all signals and point will be on the visible part of the layout so remember to include these in your signalling plan. Once you have this plan drawn up it is easy to count the number of points and signals. This, oddly enough, gives the number of levers in the box. There are many sources of information regarding how many levers would be a certain size of signal box for a given railway. Remember many boxes even when new would have a couple of spare levers for any modifications.

 

As you can see once you have the number of levers and the size of the box you cannot go wrong.

 

If you follow your chosen railway’s practice in numbering the signals and points, you can replicate this inside the signal box by having the correct levers in the correct colours.

 

A little note about signal boxes post the 1960s. Many of these stayed open as block post with only a few operating levers once the sidings etc. had been removed, so yes the box would be bigger than the signal layout would suggest. But to justify this draw up a track and signal plan of what the location might have been like pre-Beeching to get an appropriate size signal box.

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Very sensible point - but note it works two ways.  Not so long back a fellow RMweb member asked me about signalboxes for a large layout he and a friend (also on RMweb) are putting together.  The layout has a large through station with gods avoiding lines, a goods yard and loco depot so it sounds 'big' (and it occupies a large room in an outbuilding so it is big).

 

But looking at the signalling it resulted in a couple of small signalboxes - for the simple reason that the track layout is prototypical and is therefore easy to signal properly and therefore isn't overdone with largely pointless signals to take account of non-protypical movement possibilities.  Simple message - you plan in the signalling as you plan the track layout in order to check that the track layout is prototypical and would work operationally.

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FPL levers were painted blue - the shade varied from Company to Company/Region to Region;  levers working both the point and the FPL were/are painted black on the bottom half and blue on the top half.  Detonator placer levers are white with black chevrons - not the other way about (it makes a difference to where the black and white come at the top and bottom of the lever ;) )

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Hi Mike

 

You are right the signalling should be done at the same time as the track plan to achieve prototypical movements.

 

HI Paul

 

You spotted a hole in my idea. I was assuming that modellers when planning the signalling would include facing point locks, detonators etc.

 

It would be nice now and then to see a rod coming from a signal box with the detonators on the end. Well with many layouts the absence of point rodding , signal wires and pulleys can let them down. May be one day these would be features that people add to their layouts as they build them. One can but hope.

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I have seen 'det placers' painted with a single black stripe. Also, as Mike has said, with chevrons depicting either 'up' or down' passage.

 

Some boxes were partitioned, as the lever frame reduced in size. Some were even cut down to length. Nothing worse than seeing an expanse of 'white' with just a few bits of 'colour' here & there....

 

Signal wire runs in 4mm? Hmmm....

 

Ian

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Mike,

 

Memory paying tricks!  There was (is) a footbridge right next to the box at St Austell and one could look in at the Truro end of the box where the detonator levers were. I could swear they were black ...... :scratchhead:   On the topic of lever colours, is there a sort of definitive list anywhere?

 

Hi Paul

 

http://modratec.com/mud_lev01.php

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Mike,

 

Memory paying tricks!  There was (is) a footbridge right next to the box at St Austell and one could look in at the Truro end of the box where the detonator levers were. I could swear they were black ...... :scratchhead:   On the topic of lever colours, is there a sort of definitive list anywhere?

 

Clive,

There will be rodding on mine eventually, but it is a bit low on the priority list.  Must get those buildings finished first.

There are various lists Paul and they did change over the years plus there were some variations so it is very difficult to arrive at a representative list, say, the Grouped or Pre-Group period although there was allegedly some sort of RCH standard.

 

What has been consistent all the way through seems to be  red for all stop signals (including shunting and subsidiary signals), distant signal levers were green until c.1923 when distant signals arms began to be changed to yellow so the lever colour followed suit and was swapped with gong levers (which had previously been yellow and then became green).  Point levers have, I think, consistently been black for very many years while blue was used for facing point locks, lock bars and lifting bars.  Brown was again, I think fairly consistently used for things like gate bolts and locks while a single white horizontal stripe has been used for levers released by the block or electrically from elsewhere for a long time.

 

The biggest variation over the years seems to have been in the use of mixed colours and extra stripes although blue above black has long been the one for a lever working both a point and fpl while red above yellow has been used for a lever working both a stop signal and its distant signal (e.g. with I.B signals).  Direction and release lever colours have varied alot over the years including changes within a Company or Region and are best researched in a reliable source for the appropriate company etc.

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Signal wire runs in 4mm? Hmmm....

 

Model Signal Engineering do cast signal wire posts with rollers as an integral part of the casting. Then find someone with some long hair who's willing to let you have some, and you've got your signal wires!!

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Model Signal Engineering do cast signal wire posts with rollers as an integral part of the casting. Then find someone with some long hair who's willing to let you have some, and you've got your signal wires!!

"Today, police caught a man walking through Newport, carrying a large carrier bag, filled with human hair. The defendant's excuse was that the advanced starter on his model railway was at 998 yards, so didn't qualify for a motor....."

 

Ian

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In terms of signalbox size there isn't one ideal and those RtP buildings which are available are suitable for some locations but not others.  A 'box needed space for sufficient levers for all of its planned movements and perhaps a few spares to allow for changes over time.  Adding levers to an existing frame is a major task; by contrast those rendered spare over the years were simply painted white and not removed.

 

A simple two-track through station with crossover and siding might require the following:

 

Distant, home, starter and advanced starter or section signal for each main line; three point levers to operate a crossover and the point to the siding; three facing point locks for each of those points; one trap point lever controlling siding exit; three shunt (ground) signals to control movements each way over the crossover and out of the siding.  That's 14 levers for a very simple layout.  Add a level crossing of any sort and there will be a gate lock lever.  Add any further "luxuries" such as a branch line and the number of levers required starts to climb.

 

A frame of perhaps 16 - 20 levers for such a simple layout would occupy plenty of space inside something like the Kernow "Wadebridge" and "Bude" 'boxes.  Few of us model anything as complex as Shrewsbury but Severn Bridge Junction there is a massive structure (claimed to now be the largest operational manual signalbox in the world) so at something like the other end of the scale.  Between the two exists perhaps a happy medium by which we may judge the correct size of 'box for each of our individual layouts.

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42 years ago, 12yo me was always fascinated with the mechanics of the signalbox, and so decided to improve the look of my 6x4 trainset/layout, by running pseudo point rodding and signal wires from the signal box to all the (Triang Super4) points and what signals there were on the layout by using track pins with black thread wrapped round them. At the time I was well impressed with myself and my ingenuity, lol! There were 2 big drawbacks, they took up a lot of room and the baseboard took up the characteristics of a hedgehog and you had to be careful where you put your hands!...

 

Angus  

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Distant, home, starter and advanced starter or section signal for each main line;

Well, OK although most such simple stations would get by with 6 rather than 8 running signals.

 

 three point levers to operate a crossover and the point to the siding; three facing point locks for each of those points; one trap point lever controlling siding exit;

No, a station such as you describe would have a trailing crossover and trailing access to the siding, the crossover would have one lever for both ends, and the siding access and trap point would also be worked by one lever as for the crossover, no fpl levers.

 

 

 three shunt (ground) signals to control movements each way over the crossover and out of the siding.  

Depending on frequency of use and the size of budget when it was signalled there may be no shunt signals, but could be 4, each way over the crossover and in and out of the siding, if the crossover and siding access were separated by an engine length or so you could push that up to 5. 

So between 8 and 15 for the points and signals, throw in a couple of detonator placers (If its busy enough for 8 running signals) and 2 or 3 spare you can have a 20 lever frame.

 

 

That's 14 levers for a very simple layout.

I make your count 18, but with far to many point levers.

Regards

Keith

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Some companies (many I'd have thought) would use the nearest standard sized box where possible - especially with wooden or wooden topped cabins. on my line you can see boxes which have been identical when built housing slightly different sized frames.

 

The key is, I suspect, undersztanding the signalling of your proposed layout as well as sound research into the types of boxes you'd expect to find in the area.

 

No, a station such as you describe would have a trailing crossover and trailing access to the siding, the crossover would have one lever for both ends, and the siding access and trap point would also be worked by one lever as for the crossover, no fpl levers.

 

A trailing crossover could have a FPL at one end if it was required for passenger moves, Brough East on the Hull - Selby line is arranged in this way - but only for trains going from the Up platform back over to the Down main. My crossover seems not to have had the same intention so requires to be clamped (now the 5mph rule's gone) for any passenger movements.

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Some companies (many I'd have thought) would use the nearest standard sized box where possible - especially with wooden or wooden topped cabins. on my line you can see boxes which have been identical when built housing slightly different sized frames.

 

The key is, I suspect, undersztanding the signalling of your proposed layout as well as sound research into the types of boxes you'd expect to find in the area.

  

A trailing crossover could have a FPL at one end if it was required for passenger moves, Brough East on the Hull - Selby line is arranged in this way - but only for trains going from the Up platform back over to the Down main. My crossover seems not to have had the same intention so requires to be clamped (now the 5mph rule's gone) for any passenger movements.

For 'many' I suggest substitute 'virtually all' (depending in some cases on what their contractor was supplying).  And in days of yore at minor stations it would be unusual to find them with a signalled move for regular train reversals - that sort of thing is more recent I think (having replaced long lost bay or loop platforms etc.

 

Incidentally Severn Bridge Jcn has a 180 lever frame (I even have a pic of No.180 :O) but there are quite a lot of white levers and spaces in that frame nowadays due to a lot of rationalisation since the frame was re-locked c.50+ years ago.  In the not too distant past, well the 1960s/70s, a a frame of that size was still some way short of the largest mechanical frames still in use on BR. 

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Incidentally Severn Bridge Jcn has a 180 lever frame (I even have a pic of No.180 :O) but there are quite a lot of white levers and spaces in that frame nowadays due to a lot of rationalisation since the frame was re-locked c.50+ years ago.  In the not too distant past, well the 1960s/70s, a a frame of that size was still some way short of the largest mechanical frames still in use on BR. 

Allowing for the supporting girders between sections, Severn Bridge frame would be about 14 inches long at 4mm scale.

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"Its also easier to build a bigger box and have it a bit empty rather than have to rebuild a smaller one..."

 

It was not unknown for a box to be built large enough for a planned expansion which never happened, so it ended up looking over-sized. Similarly, some boxes were extended, then extended again, and ended up more than twice their original size. Many were moved intact - even brick ones!

 

Getting back to the OP, another 'problem' is the use of RTP model boxes not really appropriate to their imagined location and/or time period. There is one kit of a GWR box (I forget the manufacturer) which is based IIRC on Highley? - nice, but to a McKenzie & Holland style which was relatively rare for the GWR. Similarly, something like the Wadebridge/Bude style box (a mid-1890s design) would be totally wrong for a L&SWR/SR layout where the signalling would have been installed in the 1870s/1880s and unlikely ever to have warranted a replacement box after only a few a years.

 

Incidentally, on the subject of detonator levers, whilst the white chevrons pointed upwards or downwards depending if the line was Up or Down direction running, levers for bi-directional lines either had them pointing both ways or used straight bands!

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Allowing for the supporting girders between sections, Severn Bridge frame would be about 14 inches long at 4mm scale.

Found this picture in my odd bits for sorting box. I think it shows 9/10 of Severn Bridge frame, don't remember visiting any other large LNW frame with WR lever name plates.

post-9767-0-64896800-1360966436.jpg

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For 'many' I suggest substitute 'virtually all' (depending in some cases on what their contractor was supplying).

The main exception I thought of was the North Eastern with its S1 type boxes - being all brick there was the ability to quite easily adjust sizes to suit the location. Once you start looking at these it's quite surprising just how many variations there are when you start looking at these boxes!

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It also depends on the period. The Midland (And probably most other railways) regularly replaced their boxes for a variety of reasons so you need to be careful. My Lancater layout had boxes replaced in the 1890's and then in 1933 the two were combined into one and the whole signalling was changed. Incidentally some of the groun d dignals were made 10 or 12 feet tall (Minature semaphore in reality,) so that they could be seen from the new box. Even then the new box was the same size as one of the ones it replaced.

 

jamie

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The North Eastern Railway regularly extended brick built boxes - the box at Botanic Gardens in Hull bore mis-spaced locking room windows which indicated this rebuilding, but at the extant Crabley Creek Signal Box had the locking room wall rebuilt to respace the window so you wouldn't know it hadn't always been like this. Only the off set chimney to the rear gies the game away.

 

6351035796_1deefd17b2_b.jpg

Crabley Creek Signalbox by JamesWells, on Flickr

 

However, Crabley survives from the pre-1904 quadrupling, other locations (mostly) received new boxes to cope with the additional requirements.

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On a slight tangent to this thread, can anybody explain signal box dimensions for me. The dims for the Saxby & Farmer type 2 at Hackbridge (LB&SCR) in 1868 are given as 12' x 10' x 6'3". I have several photos of this box and can't understand where the 6'3" comes from. If the first two numbers are the footprint of the box, the height should be about 12' to the gutters.

 

David

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On a slight tangent to this thread, can anybody explain signal box dimensions for me. The dims for the Saxby & Farmer type 2 at Hackbridge (LB&SCR) in 1868 are given as 12' x 10' x 6'3". I have several photos of this box and can't understand where the 6'3" comes from. If the first two numbers are the footprint of the box, the height should be about 12' to the gutters.

 

David

Signalbox dimensions tended very often to refer to the floor size (i.e. internally), not to the external measurements and that could well be the case here (possibly the third figure, or one of them is the floor height above rail level?).  Ideally you need find a drawing and derive the figures for measurements from that.

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