Semaphore Signals - 4mm Scale (Mainly)

[Steve Hewitt]

Lovely job although I find it interesting that it reads from a Goods Line to a couple of platform lines

Thanks for your comment.

 

The layout owner explains:

"The the Goods Loop/Siding signal is used by light engines, essentially the

passenger terminal pilot/pilots to remove and reposition coaching stock. There

are no locomotive run rounds at the terminus."

 

Steve.

[The Stationmaster]

Thanks for your comment.

 

The layout owner explains:

"The the Goods Loop/Siding signal is used by light engines, essentially the

passenger terminal pilot/pilots to remove and reposition coaching stock. There

are no locomotive run rounds at the terminus."

 

Steve.

Thanks Steve - now makes some sense.

[Steve Hewitt]

Help wanted..............

 

The next signal I wish to build is a tall GWR Stop signal with a lower co-acting arm.

There is a picture of a similar one on Page 40 of Adrian Vaughan's book on GWR Signals, except this one won't have the bracket added.

 

My knowledge of the prototype is limitted, and I don't know how the "Co-acting" was achieved.

Specifically, how the link between the single Balance arm and the two Signal arms was engineered.

 

Were there two push rods connected to the one balance arm, or was there a joint somewhere along the push rod?

 

Any information very gratefully received.

 

Steve.

[The Stationmaster]

Help wanted..............

 

The next signal I wish to build is a tall GWR Stop signal with a lower co-acting arm.

There is a picture of a similar one on Page 40 of Adrian Vaughan's book on GWR Signals, except this one won't have the bracket added.

 

My knowledge of the prototype is limitted, and I don't know how the "Co-acting" was achieved.

Specifically, how the link between the single Balance arm and the two Signal arms was engineered.

 

Were there two push rods connected to the one balance arm, or was there a joint somewhere along the push rod?

 

Any information very gratefully received.

 

Steve.

I think it might have been just a single down rod Steve - it certainly looks that way in the picture in AV's book and it would also fit with the two different types of arm as the arrangement of the duplicate (lower) arm put the lamp case to the left of the post which gave the down rod ample room to carry on to the upper (main) arm without the spectacle plate etc getting in the way.  This would ensure that the two arms moved in unison (unless the down rod broke!).

 

Incidentally it probably won't affect you but it was not permitted for duplicate arms to be mounted more than 30 feet above rail level

[Steve Hewitt]

I think it might have been just a single down rod Steve - it certainly looks that way in the picture in AV's book and it would also fit with the two different types of arm as the arrangement of the duplicate (lower) arm put the lamp case to the left of the post which gave the down rod ample room to carry on to the upper (main) arm without the spectacle plate etc getting in the way.  This would ensure that the two arms moved in unison (unless the down rod broke!).

 

Incidentally it probably won't affect you but it was not permitted for duplicate arms to be mounted more than 30 feet above rail level

Thanks very much.

I'm still not sure how the connection to the Duplicate arm is made, as the connection between Down Rod and Arm is usually a fork at the end of the rod.

There must be some sort of short down rod branching off the main one to make this lower connection?

I'll probably fabricate something and post a photo for comments.

 

Steve.

[The Stationmaster]

Thanks very much.

I'm still not sure how the connection to the Duplicate arm is made, as the connection between Down Rod and Arm is usually a fork at the end of the rod.

There must be some sort of short down rod branching off the main one to make this lower connection?

I'll probably fabricate something and post a photo for comments.

 

Steve.

Steve if you have a look at page 65 there is a very good fairly close-up picture of a duplicate arm - albeit rather unusually in position as an normal stop signal arm and you can see fairly well how the down rod goes behind the casting (which is basically he same as the normal spectacle casting but without the built up spectacles of course) and you can see the drive attachement from the down rod immediately to the right of the pivot  So basically the down rod appears to be attached in the normal way for that pattern of spectacle.

 

If you then look at the Yatton picture on page 40 you will see there is only the single down rod and it aligns with the drive points on both arms, the other drive point on the duplicate arm looks to be empty as a spot of light (or dust on the negative) is visible in its position.  Whether the rod was actually in two pieces somehow jointed behind the duplicate arm is another issue or exactly how the drive was taken to the duplicate arm off the rod is, alas, not clear.

 

Alas such signals were fairly rare by the late 1950s, let alone any later, and photographs seem even rarer.  I've looked on the 'net for pics of Box and Saundersfoot (the latter was, I think, the last really tall signal on the WR) but no luck so far.

[Miss Prism]

Incidentally it probably won't affect you but it was not permitted for duplicate arms to be mounted more than 30 feet above rail level

 

The co-acting junction arms near West Drayton (c 1920s, I don't think they lasted much beyond that) look to be taller than 30'? (There are a couple of pics somewhere in the books, but I can't remember which.)

[The Stationmaster]

The co-acting junction arms near West Drayton (c 1920s, I don't think they lasted much beyond that) look to be taller than 30'? (There are a couple of pics somewhere in the books, but I can't remember which.)

Might possibly have been the case on older signals - the 30 feet figure is from a 1920 publication.  I think the maximum for the upper arm was probably around the 60ft mark but I can't recall coming across a specific GWR figure anywhere for that dimension.

 

I'd love to know how many of these signals there actually were over the years - there were some at Longfield (between ealing Broadway and West Ealing) at one time but they would have gone in the 1930s at the latest, West Drayton is one I hadn't come across but together with Longfield it suggests there might have been other examples in the London area (which definitely had some tall signals but not with duplicate arms); the Box example was well known and lasted into the 1950s I believe and there was one at Saundersfoot (Down Starter) which was the only one I ever saw but presumably there were others?

[BR(W)]

Hello, Steve, Stationmaster, everyone.

There was a co-acting distant near King's Sutton on the down line with a sighting board for the lower arm; in the days of red distants, the upper arm was 5' and the lower one 4'. A later incarnation, with yellow arms of equal length, features in a superb 1961 image of the up CCE on the cover (and inside, of course) of Bradford Barton's "Great Western Steam in Action 4". The lower arm assembly appears to be the repainted original, but the upper is a 1930s-style enamel arm and spectacle plate.

 

Now there seems to be a single operating rod run, but how the drive and articulation is arranged behind the lower arm is not at all clear, I'm afraid. But there may be a turnbuckle in the run above the lower arm suggesting that the upper arm's position could be adjusted once that of the lower arm had been set. Does that make sense, I wonder?

 

Cheers,

 

BR(W).

[Steve Hewitt]

What a really good response!

Many thanks to you all.

 

In just twenty-four hours you have provided me with enough information to make a good stab at this model.

I'll post details of it on here of course, and you can see if I get it right.

 

From a really grateful,

Steve.

[The Stationmaster]

Hello, Steve, Stationmaster, everyone.

 

There was a co-acting distant near King's Sutton on the down line with a sighting board for the lower arm; in the days of red distants, the upper arm was 5' and the lower one 4'. A later incarnation, with yellow arms of equal length, features in a superb 1961 image of the up CCE on the cover (and inside, of course) of Bradford Barton's "Great Western Steam in Action 4". The lower arm assembly appears to be the repainted original, but the upper is a 1930s-style enamel arm and spectacle plate.

 

Now there seems to be a single operating rod run, but how the drive and articulation is arranged behind the lower arm is not at all clear, I'm afraid. But there may be a turnbuckle in the run above the lower arm suggesting that the upper arm's position could be adjusted once that of the lower arm had been set. Does that make sense, I wonder?

 

Cheers,

 

BR(W).

Thanks for that - I knew I'd seen another pic somewhere (it's on the slip cover as well!) but couldn't find it yesterday when looking through various books.  The pic is interesting (and it's not the only co-acting arm in that volume) as it uses an ordinary arm instead of the earlier standard duplicate arm although it is obviously pre late 1930/early'40s signal and there does indeed appear to be what looks like a screw adjuster in the down rod not far above the lower arm, which also boasts a sighting board.  What is absolutely clear is that there is only one balance weight and a single down rod.

[Miss Prism]

The person who would know about the nature of the rod linkage between the arms is Peter Squibb.

[Steve Hewitt]

The person who would know about the nature of the rod linkage between the arms is Peter Squibb.

I'm sure you're correct, but I don't have any contact details for him, and I suspect he's not on RMweb?

 

Steve.

[Miss Prism]

I don't have contact details for Peter Squibb - he might be contactable via the Great Western Study Group website.
 

[Steve Hewitt]

I don't have contact details for Peter Squibb - he might be contactable via the Great Western Study Group website.

 

Thanks.

I've had a look at their website.

I'd have to pay £18.00 to join to get access to their membership contacts service.

Since the bit I'm struggling with is probably hidden behind the arm/spectacle plate I'll make something that works, and hope its not subsequently proved to be a total x*x*x.

 

Steve.

[Steve Hewitt]

GWR - Tall Stop signal with co-acting lower arm.

 

I made a start be getting the components assembled:

 

The main post is made from two Masokits etched taper posts.

The lower, shorter section is intended as the base post on a bracket signal.

The upper section is the standard tapered "wooden" signal post.

 

The upper section was shortened at its lower end until it matched the size of the lower section.

I then used a length of square brass tube, indserted into each to strengthen the joint, which was achieved with lots of liquid flux to pull the solder into the joint from a quite hot iron.

 

1/32in dia brass tube was used for the upper arm bearing, with Nickel Silver etches from Les Green for the Lamp Bracket, and Upper Stage bracket and handrail.

 

The lower arm bearing was similar brass tube, with the lamp bracket made from 2mm "T" section brass.

The small hole in the post is for the fibre optic which will be used in the light.

There is also a similar one for the upper light.

 

I'm using some etches from David Geen for the Weight Bar and its Bearing:

This shot shows that plenty of filler will be needed where the folds in the etches have been made.

This will be done with 100 deg. solder or Cellulose Car Filler just before painting.

 

 

The arms are from MSE etches:

 

The ladder is also from MSE, but with 0.4mm N/S wire added to the stiles.

 

Also from MSE are the Back Blinders for the lights:

 

More to follow:

 

Steve.

[Steve Hewitt]

Foundations next...

 

First the base plate for the signal, from 0.45mm Nickel Silver:

In this top view you can see where the mainpost fits, the guide for the operating wire and the holes in which the bottom of the ladder stiles will be located.

 

Turning it over:

Here we can see the tube which ensures the post is vertical, and adjacent to it the guide tube.

The guide tube ensures the operating wire is aligned with its attachment point on the balance arm when that is eventually fitted.

 

Next we have the location tube, this time from 1/2in dia Brass.

 

This is quite a long tube, as it has to pass right through the baseboard when the signal is installed.

Its job is to ensure the signal is located properly, and to align the servo motors which will be mounted on a small sub-board, which uses this tube to maintain its correct position.

The length is necessary as the location of this signal co-incides with a baseboard supporting timber.

Total length of 50mm allows for 3mm cork, 10mm sundeala, 25mm support timber, 5mm servo sub-board and a little extra to aid removal of the signal when necessary.

 

It is soldered under the baseplate concentric with the post tube.

Having been parted off on the lathe, the ends of the tube are true, so it stands firmly in place.

 

Plenty of liquid flux, two little slugs of solder, and a blast with the blow-torch, and its done in less time that it takes to write about it.

 

Clean it all up and its ready for the post to be added:

 

In the meantime, I need to get the assembly/test frame built....

 

Steve.

 

(Edited to correct spelling and grammar.)

Edited October 8, 2013 by SteveAtBax

[Steve Hewitt]

The Assembly / Testing stand:

 

As I said in an earlier post, this signal has to be installed right where a support timber timber is doing its thing, so the main location tube has to accomodate this and is some 50mm long.

 

The assembly frame has to represent the baseboard thickness fairly accurately in order for the installation of the servos can be easily reproduced on the layout.

 

This was cobbled together from some pieces of ply and MDF I had to hand:

 

The location tube is 1/2in dia Brass, so the hole is a close fit:

 

 

There is sufficient tube extending below baseboard level for the servo mounting board to use it for laocation:

 

You can see that the post is now firmly planted, and most of the static bits of the model are in place:

 

Clean, polish, de-grease etc. then off to the paintshop...

 

Steve.

Edited October 10, 2013 by SteveAtBax

[Steve Hewitt]

A little more progress:

 

The main structure painting has been completed, so I can get on with the next tasks.

 

First the lighting:

The fibres to bring the light up from below the baseboard mounted LED have been threaded up through the Main Post, and into the rear of each white metal lamp:

 

The fibres are 0.5mm dia.

This is the lower lamp, for the repeater arm. Unusually for GWR signals it is mounted on the left hand side of the post, viewed from the front. (Necessary because the post here is too fat to use a conventional lamp mounting and arm.)

 

This is the upper lamp, mounted in the convention place.

 

I've installed the main Down Rod, from the upper arm to the balance arm.

This is 0.4mm dia Nickel Silver wire, blackened with "Gun Blue".

 

Here it passes through one of three Rod Guides, to stop it buckling.

 

The balance arm with the Down Rod (on the right) and the Operating Wire (on the left).

(The arm pivot is just a Lace Pin at present.)

 

This is how I've decided to link the Down Rods for the two arms:

 

I've used two short lengths of very fine brass tube, soldered together.

The tube is 0.6mm O.D. and 0.4mm I.D.

 

At present these are free to slide on the Down Rod.

The short Down Rod from the lower arm will be located into the currently empty tube.

The assembly will then be adjusted to ensure both arms move correctly, then the tubes will be locked in place on both Down Rods with a little Loctite 601.

 

We shall see if it works.......???

 

Steve.

 

[Steve Hewitt]

But first, some more on the lighting:

 

Here are some details of the LEDs I use, and how I use them.

 

The LEDs are "Gaslight" LEDs from Helmsman Railways.

As their name implies, they are supposed to give an "off white" gas light colour.

(I'm old enough to remember having gas mantles in our first caravan - a lovely warm glow).

 

I think these LEDs are very good for Oil Lamps as well.

 

Here's the basic LED:

 

They are supplied with resistors and diodes, should your power source require them.

I use a 1K Ohm resister which allows a supply voltage of 9 to 15 volts DC.

 

I always use a 9v supply - a PP3 battery!

 

The LED is secured in a short length of brass tube, with an ID of 1/8in. (5/32in OD).

Thick superglue or rapid epoxy is fine.

 

The resistor is soldered to the positive lead and tails about 6in long added:

A small two pin plug (from All Components) finishes off the connections.

 

A standard battery connector is used, with the mating two pin socket attached.

 

Here's what the light looks like:

 

The optical fibres from the signal lamps are terminated in a little brass turning:

The fibres are glued in place and trimmed back flush with the end.

 

This turning is made to be an easy fit in the tube containing the LED, and of a length that keeps the end of the fibres up close to the LED:

 

This is what you get on the model:

 

 

Back to the mechanical bits now...

 

Steve.

[Steve Hewitt]

Installing the Servo Motor etc.....

 

This is the servo I've chosen for recent signals, it is a Tower Pro 5 gram model.

Nothing fancy and at the cheaper end of what's available.

 

Earlier I mentioned aligning the servo assembly by the use of the signal's location tube.

This is the little board on which it will all be built:

The two small holes are for the fixing screws.

 

The 25mm timber bracing the baseboard runs in the direction of travel, so the screws need to be positioned in front and behind the signal.

 

Another off-cut of plywood is used as a mounting for the servo motor:

 

Like this:

 

Next steps will be to fix these together so that the correct alignment between the operating wire and the servo motor is achieved...

 

Steve.

 

[Steve Hewitt]

Continuing with the Servo motor...

 

How is the operating wire to be connected to the servo motor?

A piece of 1/16 brass tube, bent to a right angle and soldered to the operating wire will locate in the servo's "Horn" (the crank which moves in an arc as the servo is driven by its controller)

 

To facilitate soldering to the operating wire (which has already been sleeved up to 1/32in dia to run smoothly in its guide tube), this tube is filed part way through:

 

 

The Horn is also prepared to accept the brass tube:

 

 

The tube is cut to length and placed in a suitable position so the distance below the baseboard can be measuredmeasured:

 

This gives the position for the servo motor's shaft below the baseboard.

The servo motor's support is cut to the correct length, and its base enhanced with a piece of wooden beading.

 

The servo motor must now be set to its "mid-throw" position, before the Horn can be fitted.

The GF Controller I'm using has a "Safe" facility to do this:

 

 

Connect the servo to the controller, set the Safe switch ON, and the job's done.

The controller will hold the servo in this position, or return to it accurately at any time the "Safe" switch is ON.

 

The Horn is now located on its splined shaft, in as near a horizontal position as possible, and the servo board glued in place so that the operating wire lines up with its brass tube and the horn etc.

 

With the servo motor in "Mid Throw" or "Safe", the signal arm and balance weight can be set to a similar mid-position:

 

 

The operating wire will have moved inside the 1/16in brass tube to its correct position, ready to be soldered:

 

A drop of liquid flux, a little solder on a hot iron, a quick touch and its all secure:

 

Move the Controller out of "Safe" mode, and with a control switch connected, its takes but a few seconds to set the signal up in its Danger and Clear positions:

 

 

 

Next to add the lower arm and get it to work in a proper "Co-acting" manner.....

 

Steve.

[Highlandman]

As always Steve, a fantastic set of instructions and pictures on how to complete a signal installation. By following your methods I have had the confidence to successfully complete two GWR starter signals and am part way through a bracket. At the moment I have not arranged for mine to be lit but am willing to have a go on my next attempt. One question though, do you use the battery only for testing purposes or is that a permanent arrangement to power the LED's and fixed to the layout by some other means.

 

All the best.

 

Andy

 

edited for spelling errors

Edited October 20, 2013 by Highlandman

[Steve Hewitt]

As always Steve, a fantastic set of instructions and pictures on how to complete a signal installation. By following your methods I have had the confidence to successfully complete two GWR starter signals and am part way through a bracket. At the moment I have not arranged for mine to be lit but am willing to have a go on my next attempt. One question though, do you use the battery only for testing purposes or is that a permanent arrangement to power the LED's and fixed to the layout by some other means.

 

All the best.

 

Andy

 

edited for spelling errors

Hi Andy,

 

Thanks for your comments.

I'm glad you have found my postings useful in your own modelling. That's what I hoped for when I started this topic.

 

Yes, the battery is only used in the workshop or sometimes at demonstrations.

I don't have a railway myself, but I recommend using a small 9 to 12 volt DC power supply for more permanent installations.

At my Club - Blackburn & East Lancs MRS - I used a redundant power supply from an old telephone handset when I installed the three new signals on our Oxenholme layout. The original signals were never lit, but I built the new ones on the extension to my latest specification.

 

Steve.

[Steve Hewitt]

The Co-acting lower arm....

 

The arm was prepared with a short "Down Rod":

 

This was threaded into the twin tubes shown earlier:

I eventually soldered this joint rather than use the Loctite as earlier intended.

 

The arm is retained by the Back Blinder, soldered to the arm shaft:

In this later shot, you can see the boards for the lampman's stage have been added.

 

The lower arm in its Clear position:

 

Here's the finial at the painting stage. Being white metal they are quite prone to damage, so I fit them late in the assemly sequence:

 

The LED is mounted on the servo board, by encapsulating it in Araldite Rapid:

 

Here's the top stage with the boards in place:

 

And here are "Stop" and "Proceed" shots of the completed signal:

 

 

And finally for today, a bit video:

 

Steve.