Adrian Musgrave – Signals

Semaphore Signal Construction for Lewes

Figure 1 – It all starts with a picture of the prototype…we are lucky here that it is a beautifully clear photograph with some helpful detail features with which we are able to ascertain the signal’s dimensions – the signal dolls are placed at 6’ centres, the height of the safety rail around the landing is 3’, and the ladder rungs look to be placed at 10” centres. Where you do not have a scale drawing for your chosen subject, always look for such dimensional indications to assist you in your building.
Photo by H C Casserley, copyright unknown.
Figure 2. Just to put our signal building efforts into context, this is what we are eventually trying to accomplish for Lewes. The signal we are starting with is at the far right of the picture. If you feel you need a bright side to look on, then maybe be thankful you are not responsible for constructing the trackwork…
Photo by Cedric Wares, courtesy of Glen Woods.

As a preface to this offering, can I make the following disclaimer? I mention assorted products from various firms – I have no financial or business interest in these firms apart from being a satisfied customer. When soldering please do so safely. Always work in a well ventilated area and consider eye protection. Be scrupulous in washing your hands after performing any soldering work and definitely before eating or drinking – which should not be done anywhere near your work area! Beware of the various substances you will be working with – corrosive / poisonous etc and treat them with the caution and respect they deserve. Oh and finally, remember to enjoy the journey in this great hobby of ours!

Figure 3. Next, we need to get ourselves a base to mount our signal on – here we are using K&S 1” brass strip which will be trimmed to 1½” in length. This will be sufficient for our signal which has both front and rear ladders. Mark out and cut the signal base from the strip, and while you are at it, cut out an identical strip which we will use for the permanently mounted platform base which will be  eventually set into the platform surface. On the underside of our signal base will be soldered a ½” length of 19/32” brass tube, this is designed to telescope into a permanent base which will be set into the platform surface. The signal can therefore be removed if required for ease of maintenance or for safe storage during transit.
Figure 4. The main signal base and the platform mounted permanent base having now been cut from the main strip with the two sections of tubing that will telescope into each other and allow for the removal of the signal when required. Mark a point in the exact centre of the platform mounted permanent base, and then drill out a hole with a 5/8” drill – into this will be soldered the length of 5/8” tubing.
Figure 5. Once the permanent base has been drilled out and the 5/8” tubing soldered to it, we need to turn our attention to the piece we are using for our signal base. We need to solder the length of 19/32” in the centre of it so it will accurately align with the permanent base when telescoped. 
Figure 6. The length of 19/32” tubing has now been soldered to the underside of the signal base and the assembly telescoped into the permanent base. Check that any pieces of stray solder have been cleaned up to enable an exact fit of both pieces when telescoped.
Figure 7. Next job to be done is to clamp together both pieces and drill four 1.3mm diameter holes in the corners to take 12BA countersunk screws which will then hold both pieces together on the layout.  Carefully countersink the holes checking as you go – the brass strip is only 32 thou deep so there is little margin for error. Drill a 4mm hole in the centre of the signal base, which we will use for the operating wires to the signal arms to pass through, as well as any wiring for the signal lamps and Banner Repeater.
Figure 8. Here we are looking at the underside of the permanent platform base with the signal base telescoped into it. We need to accurately solder two 12BA hex nuts to the underside of the base on opposite corners into which the 12BA CSK screws will locate and secure both assemblies together. The remaining two holes on the permanent base will be used to secure that assembly to the platform on the layout.
Figure 9. I find it easier once the signal’s base is made to set it into a temporary base on which to work on the signal, and for this I use a piece of 2” x 2” with a ⅝” hole drilled to a depth of ½” using a drill stand – we want the signal to stand at exactly 90 degrees in all planes. Signals utilising bullhead rail for posts can be tricky to get to stand true, using this construction method we can add various temporary supports to assist us in succeeding in this aim.
Figure 10. Once we have finished the signal’s base, we can turn our attention to the signal post. This signal post is constructed from two pieces of used bullhead rail joined together using bolted turned spacers. We will be using 0.5mm brass wire to represent the turned spacers. There are two of these ‘leg’ assemblies that form the signal post. Firstly, we need to cut ourselves four 60mm lengths of bullhead rail for our 15’ post. Align both railheads and tin the inside of the rail, then temporarily solder both rails together. Clamp this assembly in the drill stand. We need to carefully drill out a series of 0.5mm holes along the rails’ web set at (10mm) 2’6” centres to accommodate the spacers. Do this for both post ‘legs’.
Figure11. Unsolder the two pieces of rail and this is hopefully what we should be left with – two pieces of bullhead rail with a series of parallel 0.5mm holes in the centre of each rail web.
Figure 12. Once we have our two pieces of drilled bullhead rail, we need to construct a simple jig which consists of nothing more complicated than a piece of wood with two 1/16” holes drilled into it and into which we place two short lengths of 1/16” brass tube. The sections of rail are placed either side of the 1/16” tube which gives the correct spacing between the lengths of rail. The spacers are represented by tinned 0.5mm wire which we insert between the parallel holes and solder in place.
Figure 13. When the two lengths of rail have been joined by soldered wire representing the spacers, the excess length of wire is trimmed and then filed to represent the bolt heads. We are then left with the two ‘leg’ assemblies which together will make up the post of our signal.
Figure 14. Having formed the ‘legs’ we now need to attach them by means of soldering to the removable signal base. The ‘legs’ need to be a scale 1’ apart (4mm). Our square 2’ x 2’ offcut of wood should be used to ensure that the ‘legs’ stand at 90 degrees when soldered. Into the offcut of wood we drill a 4mm hole, and then leaving the drill bit in the hole we have just drilled, we place the signal base over the drill bit utilising our previously drilled 4mm hole. The drill bit should now be standing at 90 degrees in all planes. Over this drill bit we place a short length of 3/16” aluminium tubing to which we can lightly clamp our two ‘leg’ assemblies, ensuring that the railhead is on the outermost part of the post assembly. Once this has been done we can then solder both ‘leg’ assemblies to the removable signal base. The 3/16” aluminium tubing gives us the required 4mm between the ‘leg’ assemblies, and should not get inadvertently soldered to our structure. 
Figure 15. This, then, is what we should hopefully end up with – our two sets of ‘legs’ which together form the post of our signal, soldered to the base at 90 degrees in all planes, ready for us to attach the bracket structure…
Figure 16. And so to the bracket structure and landing. We are going to use parts from the Model Signal Engineering SR Offset Signal Bracket S008/1 kit to assist us in construction. We do not need the full length of the bracket for our signal, so we need to remove a short section at the end of the bracket, and then solder a small length of scrap etch to form the new end of this piece. Once this has been soldered in place, it can then be filed to the desired profile – above is the “before and after”. Tin the top of the bracket where it will be soldered to the landing. The landing itself needs to be slightly longer than the etch supplied, but all we need to do here is solder two pieces together, and then cut to the desired length. Tin the underside of the landing, drill out the holes for the handrail stanchions and then cut out suitable holes to locate the signal dolls and the Banner Repeater equipment and accommodate any down wires from the signal arms.
Figure 17. The dolls on our signal are relatively short and will need reducing in size from those supplied with the MSE etch S0022 Stevens & Co Lattice Signal Dolls. Cutting needs to be done very carefully so as not to distort these delicate etches. Using a square offcut of wood, bend the shortened etch to 90°, and then solder along the inside of the angle which will help to strengthen the part. Repeat the same process for the second etch, and then using the jig which is helpfully supplied with the kit, solder both pieces together and you should be left with a square lattice doll. On the right is a nearly completed doll with balance weight, lamp bracket and arm bearing tube fitted and an UQ signal arm temporarily in place to check for the correct position of the signal lamp. The signal lamps on Lewes will be illuminated by micro LEDs, and so will need drilling out to accommodate same. The finials to the dolls will be fitted at a later stage to avoid getting damaged.
Figure 18. For each doll there are a number of assemblies that require constructing, including the balance weight and bracket, signal arm spindle bearing and the lamp bracket. Most of these parts can be found on MSE kit S0012/1 Upper Quadrant Signal Parts. All the parts we will be using are small – if you are able to work over a tray or similar you will save yourself both time and irritation looking for dropped or lost parts…I find that the bracing for the lamp bracket is very easy to so lose, soldering it to the bracket I find is easier if the bracket is left partially on the main etch, tinned and then bent through 90°. Holding the bracing with needle nose tweezers, place it in the etched line on the bracket as seen above at the far right hand end of the main etch, touch briefly with the soldering iron and it should form a good join almost immediately. The balance weight itself consists of four separate parts – two balance weight levers and two weights and again construction, I find, is made easier by leaving one of the balance weight levers on the main etch and soldering the other parts, once correctly aligned, to it. The bracket folds up and we can reinforce the joins with a small amount of solder. A short length of wire should then be inserted through both pieces to act as the pivot. The arm bearing is simply a short length of 1/16” tube which is soldered to the left-hand side of the doll at right angles – again a very simple jig will help us achieve an accurate fit.
Figure 19. The two dolls awaiting the fitting of their signal arms and lamp castings. The next job is to fit them to the signal landing. 
Figure 20. The dolls with signal arms temporarily fitted to check for clearances and alignment. The signal arms still await the fitting of the spectacle lenses – a job we will tackle later on in the project.