Turnout construction - Bullhead rail.

Discuss the prototype and how to model it.
Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 12:23 am

DEAR ALL. THE AIM OF THIS THREAD IS TO FOCUS ON THE VARIOUS STAGES OF CONSTRUCTING A TURNOUT. I UNDERSTAND THAT YOU MAY WISH TO ASK QUESTIONS AND SO HAVE NOW SET UP A SEPARATE TOPIC FOR THIS PURPOSE IN THE HOPE OF NOT INTERRUPTING THE FLOW OF THIS THREAD, WHICH I HOPE WILL BECOME A USEFUL REFERENCE SOURCE.
THANK YOU FOR YOUR CO-OPERATION.

Questions Thread

It has been my intention to update the society digest sheets covering Turnout construction for some time now. The meanderings of my Brimsdown thread into P&C (Point and Crossing) territory have convinced me of the need to explore this subject as a separate issue, hence this thread. It is my intent to break the subject down into parts. Starting with the tools I use, (of which there are quite a few) then the timbering and the Crossing Vee and its components. Whether I cover the rest of the turnout as a single thread or start a separate topic is something I have yet to decide.
Let me also apologise for the variability of some of the photographs. Indoor lighting is not the best to work under, but these dull winter days leave little option and close ups with macro lenses add another element of difficulty. Digital cameras amaze me sometimes with their capabilities. At least one can check the results quickly and try again to get a better result.

TOOLS.
Here are some pictures of my standard track building tool kit. It is possible to build track with fewer tools than this, but this collection has been amassed over a considerable period of time and they all have their uses, which I shall explain as I go.

Indelible marker pens (fine and coarse) for marking the rail. A selection of files mostly needle files. The large file is used for the switch blades, which I shall come to later.
Tools 1.JPG


Abrasive blocks and society filing jigs for Crossings and switch blades.
Tools 2.JPG


This is a bit of a bone of contention. A well used Exactoscale Crossing Vee assembly jig.
I find this item so very useful and yet it is currently unavailable. Etched in Stainless steel, one can solder Vees together with impunity knowing that the solder will not stick to it, unless that is you plan to use stainless steel rail. Prior to this, I needed to carry around a block of chipboard with a variety of crossing angle stuck to it with double sided tape if I was doing a demo.
Tools 3.JPG


A selection of gauges and fine drawing pens to mark the timbering.
Tools 5.jpg


Cutters and pliers.
Tools 6.jpg


The all important press and punch tool, in this case the Joe Brook Smith pattern.
The wooden block (supplied) holds the press tool at a more comfortable working angle. The only problem is that it also covers the holding screws for the combined punch a closure tool, so don't glue the block on permanently. I use foam double sided tape.
Tools 7.jpg


The soldering kit. The flux I use is Carrs orange label. This is a Rosin based flux that leaves behind a non corrosive residue. It can be removed or thinned with Meths if desired. I do not use an acid flux even for steel rail.
Tools 8.jpg


The double sided tape that I use. 12mm. This can be obtained on line from http://www.craftcreations.com.
Keep it in the bag between use as this helps prevent the adhesive drying out.
Tools 9.jpg


TIMBERING.

The template is stuck it down on a sheet of 6mm MDF with Pritt stick at the corners only, double sided tape is attached as shown.
The subject of this exercise will be the B-10 turnout at the bottom.
Timbering 1.jpg


This unimposing little device is a jig to check for invalid timber lengths. The hashed area is the length between the longest standard timber and twice the shortest length, at least for 8'6" timbering. If you end up with a remnant in the no go zone, it won't fit anywhere, with the possible exception of a tandem turnout.
Timbering 2.jpg


A selection of leftovers from a previous session, to be used first of possible.
Timbering 3.jpg


The usable ones in place with the remainder compared with the test strip. The longer ones will be cut in two for shorter lengths, but the two to the left are in the no go zone. They will be cut down.
Timbering 4.jpg

Timbering 5.jpg


A long timber in place on the template.
Timbering 6.jpg


Place the blade in position where the timber requires to be cut and press firmly down. By pulling up on the outer end whilst under tension, the timber will break cleanly.
Timbering 7.jpg


The amount of pressure applied may be judged by the depth of the cut in the timber when the blade was removed before breaking the timber. It is roughly the thickness of the first layer of the ply.
Timbering 8.jpg


All the timbers cut to length.
Timbering 9.jpg


All the timbers are marked with a 0.2mm drawing pen to show where the rivet positions should be. I have only shown the crossing area as this is the part I shall be concentrating on first. The long line on the C timber is where a larger headed rivet will go.
Timbering 10.jpg


The rivet press in action, punching the holes. The design has a self centring action by pushing the timber to one side. I proceed one timber at a time. Remove one, punch and rivet it, then replace and do the next and so on.
Timbering 11.jpg


The fancy little gadget for placing the rivets into the holes. It is sprung loaded, so the action is fairly obvious. Place through timber into rivet shaft and press home. Not the sharpest of pictures.
Timbering 12.jpg

Timbering 13.jpg


Setting the rivets. I will of course align the rivets a bit better before pressing down. When closing the rivets is important to get consistent results. This is where a press tool scores, although even here there can be small variations between both sides when closing two rivets at once. Consistent pressure is the key. Even so I do still occasionally have to turn a timber round and repeat the pressing action.
Timbering 14.jpg


The finished result. Note the single large rivet on the C timber, (third from the crossing nose) rather than using two standard rivets that would need the head cut down in width. This does happen with the check rail rivets and the blue handled flush face cutters are ideal for this task.
Timbering 15.jpg


Finally give everything a clean with an abrasive block, then sweep off the debris with the dust brush, prior to the next step which will be fabricating and fitting the rails for the crossing area.
The cleaning blocks I use are made by Schleiffix (Klingspor). I have tried other makes, but some tend to leave a rubbery deposit on the surface afterwards. If the block smells of rubber it has too much solvent in it. These ones do not smell and are much drier as a consequence. This particular one is 60 grit, which is really too coarse. 120 grit would be better with a 240 grit for final cleaning up.
Timbering 16.jpg


Tony.
Last edited by Tony Wilkins on Sun Feb 11, 2018 1:03 pm, edited 2 times in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 5:11 pm

THE VEE 1.
Having just lost 3 hours work by trying to cover all the Vee rail topic in one post due to a computer glitch, I will try a different tack from now on and post in smaller chunks.

The first task is to decide what type of rail you are using. The pros and cons of each material are not an issue here. The trackwork on Brimsdown is all Hi-Ni rail, but this particular B-10 left turnout will be built utilising steel rail. I shall however be using some pictures of a curved C-12 in Hi-Ni later to illustrate some salient points.
There are two ways to tackle a 1:10 crossing utilising the society Vee filing jig. Perhaps the easiest way is to make both Vee rails out of one piece of rail and file the two ends to shape before cutting it in two as shown by the length of rail at the bottom of the picture shows. The problem is that the individual lengths of rail you need are not long enough to be held by the clamping screw and washer.
Vee 1.jpg


Set the Vee assembly jig to the required angle.
Vee 2.jpg


A trap for the unwary, with bullhead rail, the head is deeper than the foot as can be seen clearly in this picture. The head is nearer the camera.
Before filing anything it needs to be determined which side of the rail needs filing. Start with the point rail. Hold the point rail (as is normally the case, the straight or main rail) in position (head uppermost) on the template to determine the main running face. This is the one to begin with. Place the rail in the vice with this surface clear of the jaws ready for filing. Remove enough material to get down to about the centre of the web at the tip. The length of filing is not critical at this stage but aim for slightly less than the crossing angle in millimetres. Also note that the angle of the end of the web cut is at right angles to the rail. This indicates an even vertical cut. I use a No 2 cut for this.
Vee 3.jpg


After filing, examine the rail for burrs and remove any with a fine file before they find your fingers.
Some of you may recognise the vice. It is a unimat machine vice attachment bolted to their milling table. Any decent small vice will suffice as long as the top inner edges of the jaws have a good sharp edge. The reason for this will become apparent later when we come to look at switch blades.
Place the now shaped piece of rail in the vice such that the last millimetre or so of full rail profile is just into the edge of the jaws and do the adjuster up finger tight trapping the rail.
Vee 4.jpg


Without altering the jaw setting, Pull the rail out of the jaws and then gently push the rail back into the jaws feeling for the point of resistance where the cusp of the full rail profile starts and then bend the rail against the jaw edges to transfer the angle from the filed side of the to the unfiled face, thus.
The aim is to restore the running face to a straight line.
Vee 5.jpg


Using the same file, place the rail on top face down.
Vee 6.jpg


Place finger on top and gently rub to and fro. The advantage of doing it this way is that you will find it much easier to produce a flat surface than by using the file on top in the traditional way as there is a tendency to rock the file whilst moving it, at least there is when I do it.
Vee 7.jpg


The result. Note how the witness marks show a good line into the main body of the rail. See how have changed from across to along the rail except for the length toward the tip. This indicates that the tip end of the ail needs to be bent a fraction more and a little further filing is required.
Vee 8.jpg


The rail in place in the Vee filling jig. Due to the lack of length, a separate piece of rail (not shown) is placed under the clamping screw and washer and adjusted so that this piece of rail is held at the correct position. A firm grip will be needed during filing as the file will tend to pull the rail back on the return stroke. (I file more down the length of the block rather than across it.) It may also be found necessary to support the rail where it is proud of the block as there is a tendency for the rail to twist downward and the resultant web cut end will not be square to the rail. Keep filing until the top surface of the rail is flush with the jig surface.
Vee 9.jpg
Last edited by Tony Wilkins on Sun Feb 11, 2018 9:33 pm, edited 1 time in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 7:21 pm

VEES 2.

Having now completed the point rail, the process needs to be repeated for the splice rail. This will however be of the opposite hand so the first cut is done to the other side of the second piece of rail and then basically everything is done with the rail the other way up.
Once both rails have been made insert the point and splice rails into the crossing vee assembly jig and check the fit.
Vee 10.jpg


Whilst all these aids to construction help. It is perfectly possible to make your own vees without most of them. You will still need to make some sort of Crossing vee assembly jig whether it be out of cardboard or whatever. Once the stage of filing the second side of the rail is reached the technique is to take a few cuts off the rail and then place the rail in the vee jig and check to see which way the error is. Adjust the angle you are filing slightly to suit and then repeat the process checking regularly and adjusting accordingly. It does not take too long to learn how to make quite acceptable vees. I used this method for many years prior to obtaining the jigs and still do when a non standard crossing angle is needed.

Remove both rails and clean the inside faces with the cleaning block, clear away the debris as before.
Place the point rail back in the jig, flux liberally (Orange label) the inside face of the splice rail where it is to be soldered and replace in the jig ready for soldering. Put a little solder on the top surface of the rails with the soldering iron to aid heat conduction and then feed in more solder down the middle of the vee rails. The heat should draw the solder into the joint. While the solder is still molten make sure that both rails are fully inserted into the jig both laterally and vertically as they have a tendency to move whilst being soldered. That is what the old wooden handled screwdriver is used for, not fingers!
This is one of those shots where you need at least three hands. One for the iron, one to feed in the solder, one for the screwdriver and at least one for the camera. I leave you to guess which one did not happen.
Vee 11.jpg


A word about soldering irons. When I first started work I discovered Weller 48W temperature controlled soldering irons. They were in a different league to the 25W Solon soldering iron that my father had and I borrowed. Although 25W should be adequate for most needs, the problem is that the basic soldering iron is on continuously and when not being used is only cooled by the surrounding atmosphere, so gets too hot and the bit rapidly oxidises.
With the temperature controlled design, the iron heats up until it reaches the working temperature and switches off, only switching on when needed to maintain the bit temperature. Their advantage is that reserve of power allowing them to cope with the heavier tasks when needed. The bits do still oxidise but nothing like as quickly. The problem is the cost, which is not really worth it unless you use it a lot as I do or do electronic soldering, something I did quite a lot in the past. There are other makes and Antex do a range of temperature controlled irons, some at reasonable prices.
I find steel rail needs more heat than Nickel Silver to make the solder flow and this requires a larger bit. The solder I use is perhaps unsurprisingly multi-core solder meant for the electronics industry mostly 0.7mm diameter, but I do have some thicker stuff as well. I have used it for etched kit construction, but the Carrs range supplies better solders more suitable for this purpose now. But that is another subject.

As before place the joint side of the vee face down on the file and rub to and fro to remove any step that may have been left by the soldering process.
Vee 12.jpg


This is what we are aiming for, a nice smooth surface between splice rail and point rail.
Vee 13.jpg


It can also be worthwhile giving the other side of the vee a quick rub down to remove any regularities.
File the tip of the point rail back to where the thickness is approximately 10 thou or 0.25mm for the blunt nose.
Vee 16.jpg


The next step is to draw file the top edges of both rails to restore the radius to the corner profile. This is achieved by moving the file from side to side rather than fore and aft. Vary the angle of the file to the rail as we are trying to remove the sharp corner left by the earlier filing. The file I use for is at least No4 Smooth file. The one pictured is intended for cleaning relay contacts and feels smooth but gives a superb finish to the surface.
Vee 14.jpg


This is the result we are trying to achieve. Note that the two radii have merged toward the tip causing the top edge of the rail to subtly fall toward the tip.
Vee 15.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 9:15 pm

VEES 3.

The next step is to mark up the exit rails ready for trimming to length. The nose of the point rail should be placed such that the tip overlaps to the far side of the rivets. In this picture the black pen marks look as though they are past the rail end marks on the template. In fact the near side of the mark is directly above the joint mark on the template and the difference is down to parallax error. Carefully cut the ends of the rails with the Xuron rail cutters and true up the ends with a No 4 file.
Vee 17.jpg


Melt some solder on to the two rivets at A chair and when solidified add flux.
Vee 18.jpg


Position the trimmed vee rails into place with the nose resting on the solder blob.
Vee 19.jpg


With a finger gently holding down the vee at about the mid length, place the iron on the solder. As the solder melts several things are likely to happen. The nose of the vee drops into the molten solder, but as the blob of solder melts from the side where the heat is coming from, the nose tends to drop sideways as well as down. It may also move in other unwanted directions. As soon as the solder melts remove the iron and attempt to position the vee correctly and hold it until the solder solidifies. This can take longer than one might expect and it is quite common to take ones finger off too soon whereon the rail moves and the solder promptly sets with the rail in the wrong place. Most of the solder is behind the rail in this picture as that is the side I placed the iron and will cause problems later.
Vee 20.jpg


Flux the two end rivets for both rails and solder into position.
Vee 21.jpg


It is very important to check the alignment of the vee before proceeding any further. The straight rail should line up perfectly.
The curved road will be a little more difficult to check although in this case there is a longer straight section of rail before the vee than usual due to the B-10 combination being larger than a natural turnout. It is far better to make any adjustments now than just carry on and hope things will work out because they generally only get worse and I have ended up having to dismantle and rebuild in the past for not being critical enough at this juncture. So spend as much time as necessary to get things right before proceeding.
Vee 22.jpg


When satisfied proceed to solder the remaining joints from the far end working toward the nose one timber at a time. Making sure that the rail is held down firmly against the rivets as the solder sets. Once one reaches the joint under the splice, the rails will be firmly held in place by the other soldered joints and should not move.
Vee 23.jpg


The Vee soldered in place. I have removed the X timber so that the position of the wing rail bends can be seen. The alternative is to print out a second copy of the template to use as a rail bending pattern.
Vee 24.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 10:19 pm

THE WING RAILS 1.
This is where things start getting interesting as in my opinion, this the most critical part of the making a reliable turnout. Getting the alignment correct through the Vee relies on getting the various elements lined up correctly. A correctly positioned Vee is the first of these. The method used here has been proven over time and so is explained below in some detail.

This template was printed out some time ago, but It was only when I came to start building it that I realised that for some reason the wing rail fronts are short. This must be due to the settings used that were carried over from a previous template, in all likelihood a slip of some sort. Rather than alter it and reprint, I have decided to go with it as this may well be a situation faced in future by anyone contemplating building a slip. Usually the wing rails are longer than this which makes the task that bit easier and I shall come back to this later on.
First step, rail cut slightly over length and positioned so that the end of the wing rail is directly above the rail end on the template. It really is honestly despite appearances to the contrary. Holding the rail upright with a check rail gauge is a useful tip. The bend is marked with the wide felt tip marker symmetrically about the bend shown. The current version of Templot shows the extent of the bend on the printouts, which makes the job so much easier.
Vee 25.jpg


Place the rail in the vice with the first edge of the mark in line with the edge of the jaws.
Vee 26.jpg


Bend to half the required bend angle.
Vee 27.jpg


Move the rail out till the other side of the mark is in line with the edge of the jaws and complete the bend. Any error can be corrected as we go.
You now know the short cut I take as this does not produce a true curve, but the difference is so small that it is not noticeable. With greater angles the bend length is less anyway.
Vee 28.jpg


Repeat for the second wing rail but remember to bend it in the opposite direction.
This is where I have had to cheat a little in order to be able to take the picture. Normally I hold the wing rail against the Crossing Flangeway (CF) gauge with my fingers to check the bend angle. The spring clip is holding the rail but pushes the other end out, so the rule is there to stop that happening. Any error in the bend angle can be gently tweaked between the fingers.
Vee 29.jpg


Make sure to view from directly above. The accuracy of Templot printouts means one can follow them in total confidence.
The wing front rail length has been marked ready for trimming to length.
Vee 30.jpg


Preparing to bend the flared end. Note that this rail is actually upside down during this procedure.
Vee 31.jpg

A series of gentle tweaks produces a gentle flare.
Vee 32.jpg

Vee 33.jpg


Once again the blob of solder technque.
Vee 34.jpg


File the cut end of the wing rail smooth if not already done so, clean the underside and place into position ready to solder. If all has gone to plan, both ends of the wing rail should be in line with the the rail ends on the template ensuring that the bend is also in the correct place. Again use the Check Rail gauge to hold the wing rail makes life easier.
Vee 35.jpg
Last edited by Tony Wilkins on Sat Feb 10, 2018 11:26 pm, edited 1 time in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 10, 2018 11:24 pm

WING RAILS 2.

Once soldered to the rivet advantage can be taken of the ability to pivot the wing rail to obtain adjustment of the Crossing Flangeway gap. Obviously with a longer wing rail this become easier as there is greater distance and therefore less of a angular swing when making the adjustment.
Vee 36.jpg


Place the CF gauge between the wing and Vee rail as the rail is pivoted together. If the diverging road is curved the CF gauge will not give a true value if laid longways. I also tend to use the CF gauge vertical because as the rails come together, the CF gauge goes from leaning to upright indicating that the gap is correct. Plenty of Flux applied to the A joint and a little more solder added as the iron is applied to ensure the joint is made. The wing rail needs to be held in place with the old screwdriver while things cool enough to let go after the iron has been removed. The knack is to hold both the solder and screwdriver in the same hand. After things have cooled down check the CF gap for accuracy. The gauge should be a sliding fit. If it needs force it is too tight, but it should stay vertical when released.
Vee 37.jpg


Check the alignment. If there is anything wrong at this stage it needs to be investigated and dealt with.
Vee 38.jpg


The second wing rail in position and marked to length. Note that the two bends are opposite one another. They should technically be opposite of a line drawn through the centre of the vee.
Vee 39.jpg


Remove rail, cut to length and tidy / clean. Another solder blob. It is a technique I use frequently when needing to tack a rail quickly or even temporarily.
Vee 40.jpg


As before solder to rivet.
Vee 41.jpg


Pivoted out ready to demonstrate the principle. Singed timbers are unfortunately par for the course especially so with the greater heat needed for steel rail.
Vee 42.jpg


Second wing rail ready to be soldered. Again the clip is only there for photographic purposes.
Vee 43.jpg


Both wing rails soldered in place. Note the symmetry.
Vee 44.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sun Feb 11, 2018 12:09 am

WING RAILS 3.

With only two rivets soldered slide the CF gauge back and forth through the flangeway and check for ease of movement though the gaps. If the end of the gauge catches the knuckle bend, then something is out of line.
Vee 45.jpg


And the other way.
Vee 46.jpg


Things seem OK so solder the remaining rivets and clean up with the 240 grit block.
Vee 47.jpg


Now for a look at some pictures I took during the construction of the last storage yard turnout for Brimsdown, a curved C-12 with normal wing rail front lengths.
The process is similar except for the complication of everything being curved so there are no straight lines as reference.
A flexible steel rule is the arbiter here. Many of the steps should be familiar, just that everything has to be curved before fitting. It adds a whole new dimension to the problems of Vee alignment. The secret to success is to check and check again as you go, and if something seems wrong, sort it out before proceeding further. Do not be prepared to accept second best.
Hi-Ni rail and S4-X standards.
Vee 48.jpg

Vee 49.jpg

Vee 50.jpg

Vee 51.jpg

Vee 52.jpg

Vee 53.jpg

Vee 54.jpg

The red line across the end of the turnout is a baseboard joint.

Before finally moving on from wing rails and without pre-empting more complex trackwork, which I intend to spend some time discussing later, I mentioned in my Brimsdown thread that I had timbered a C-6 1/2 crossover with a single slip in the middle.
Vee 55.JPG


My typical approach to this is to tackle all the Vees first. This goes for Crossovers, Diamonds, Slips, Scissors crossovers (examples of which I have already photographed to illustrate). Three way turnouts are slightly different as the wing rails become part of the arrangement earlier. The reason is that getting all these correctly positioned is so important that it pays dividends to do them all first and make sure they are right before moving on. It also makes life easier with what follows if the starting position is correct.
The first Vee to be positioned was the lower one. The second one above was tack soldered at the nose and where the point rail crosses the last timber that supports both point and splice rail. Note the sleeper removed so the end mark for the splice rail may be seen. Short pieces of rail abound in this instance making life more of a challenge. The track gauge was placed in position and just dropped onto the splice rail without any distorting force being applied, verifying the accuracy of both the template and the construction. Make sure the track gauge is pushed fully to the right so that it is engaged against both faces of the vee. The splice rail is then soldered to the rivet on the same timber as the point rail and the alignment checked before further joints are soldered.
Vee 56.jpg


Earlier I mentioned making both point and splice rail out of one piece of rail. The splice rails for the other two vees are even shorter than those above due to the closer track centres, so were made at opposite ends of the same piece of rail. Being a 1:6 1/2 angle all the component rails were first made using the 1:6 filing jig and then made finer by taking a very small amount off the each rail checking against the Vee assembly jig, which had been pre-set to 1: 6.5.
Vee 57.jpg


All four vees in position.
Vee 58.jpg


This is how I gauged the two crossings to the right with such short splice rails the only option was to use a Brook Smith track gauge I had.
Vee 59.jpg


Tony

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Mon Feb 12, 2018 8:47 pm

THE STOCK RAILS.
When I started this morning I thought "there can't be that much to say about Stock rails". Well I still managed to end up taking over 30 pictures, so there must be rather more to it than I first suspected. True many of them cover the slide chairs, but there are still quite a few that don't.

The first thing to do is mark and cut the first stock rail to length. Beginning with the straight stock rail, hold in position with the track gauges to enable the length to be determined with greater accuracy. Cut and file one rail end square (as has already been done here) before marking the second end to length, cut then clean up to restore the full rail profile and de-burr. With a 1:7 or shorter crossing angle, it is possible to span the vee with the long side of the gauge for greatest accuracy.
Stock rails 1.jpg


Unless the turnout is short, typically B-6 or possibly B-7. I cut the stock rail into two pieces otherwise it is my experience that expansion can potentially cause problems if longer lengths of rail are used.
Stock rails 2.jpg


Begin to solder the rail into place. Note the green line marked on the template between the first two timbers on the left of the picture and how far it is from the vee. This marks the end of the closure rail curvature, which I shall explain in due course.
Stock rails 3.jpg


I start with every forth joint (not always possible around the crossing area due to where gauges can be sited) and allow to cool before making the next one.
Stock rails 4.jpg


Soldering steel rail with orange label flux can be challenge at the best of times. Everything needs to be scrupulously cleaned with lots of flux and heat. Even so I have occasionally found the odd length of rail that just refuses to cooperate. The fall back plan is to use the tiniest smear, and I do mean tiny, of Fry Powerflow flux (in a Yellow tub), which works every time. The aim is to use so little that all the residue burns off during soldering. However, this does not constitute a recommendation, more a measure of last resort as the residue can promote rusting. It does though not work on stainless steel rail, which I have recently had cause to test with not very encouraging results.
Working from both ends of the rail continue soldering every forth rivet.
Stock rails 5.jpg


Next start to solder the middle rivets between those already soldered. Either work alternatively from each end or in a semi random pattern. If you work from one end, you will create a hot wave of expansion that travels along the rail as you go. As the rail cools it will progressively pull the timbers out of line.
Stock rails 6.jpg


Don't forget to test each joint for soundness. This is particularly important when using steel rail as what looks like a good joint often isn't. I do so by inserting a small screwdriver blade between the underside of the rail and the top of the timber / sleeper and gently twisting. Once the middle rivets have been soldered one should be left with more or less every alternate rivet soldered. I now solder the alternate remaining joints semi randomly and finally the remaining ones again in a semi random pattern.
Stock rails 7.jpg


Once all the joints have been soldered, cut the curved stock rail and fit in a similar manner. Due to the crossing being a 1:10, the diverging track will be straight for some distance before the crossing is approached, but the first part of the rail will need to be pre-curved to match the template. This is achieved by gently flexing the rail whilst drawing between the fingers. Next cut and fit the remainder of the straight stock rail.
Now we come to the last part of the curved stock rail. This needs special treatment is it needs have have either a Joggle or a set put in it to accommodate the angle of the switch pair. Since I have never used a joggle when making a turnout, I shall explain how to make the set.
Cut a piece of straight rail just over length and hold it so that the toe end of the rail is on the rail join mark. On the full size track, the set occurs 4" in front of the switch tip. This is approximately 1.5mm in scale. Allowing for the position of the switch blade tips relative to the timber edge, (shown on the adjacent switch behind by the two red marks, and I shall come to this in a bit more detail shortly) make a thin mark on the rail head about 1mm before the timber.
Stock rails 9.jpg
Last edited by Tony Wilkins on Sun Feb 18, 2018 3:00 pm, edited 1 time in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Mon Feb 12, 2018 11:40 pm

This is confession time. Those of you familiar with Templot and its printouts will have doubtless noticed that the templates I have been using are of an old style. This is down to a legacy issue I have in as much as the HP printer I use is capable of printing paper sheets larger than A3. Some years ago I purchased two reams of A1 paper and split it down the middle lengthwise to produce in effect a double length A3 sheet. This works fine with an older version of Templot that I have running on windows XP. This is an internet free zone and it has never seen an update. Since I still have several hundred sheets of this paper left, it is a situation that is unlikely to change until either I run out of the paper or the printer dies.
In parallel with that I have Linux installed on this laptop mainly for internet based activity. This runs Templot 2 under Wine quite happily and has a generic printer driver for my printer. All fine in theory, but in practice there is no option for custom paper sizes and worse than that, I was to discover that although I have an A3+ printer, selecting A3 as the paper size just produces an A4 size printout on A3 paper, so no cigar there. This is unquestionably a problem with the printer driver and nothing to do with Templot, but leaves me with a conundrum. Back to A4 paper for printing out my Flatbottom track templates.
Be that as it may, here is a C-6.5 turnout from the crossover mentioned earlier. Despite appearances (due to camera distortion) the tracks are straight.
Spot the error!
Stock rails 10.jpg


Let us examine some of its features in a bit more detail. These switches are called semi curved.
The switch tips are both marked and annotated. The set is also marked as being in the same place when it should in fact be a scale 4" (1.33mm) in advance of the Switch tips. Something I had not noticed previously. This offset is to allow for the thickness of the tip of the switch blade which cannot be infinitely thin.
The switch planing length is shown in several different ways. The lack of rail infill, the annotated marks with the green line in between. The green line marks the end of the straight switch planing and the beginning of the switch rail radius. The stock gauge is where the distance between the two stock rails is the track gauge plus one rail thickness.
To the right of the picture a further green line will be noticed. This marks out where the switch rail radius changes to the closure rail radius. For a natural turnout these two will be the same radius. A-7, B-8, C-10, D-12, E-16, F-20.
Stock rails 11.jpg


Combinations beyond these (such as the B-10) have the same radius as the natural turnout, but a longer straight section between the closure rail curve and the vee. Note the green line just in front of the vee, this shows where the closure rail curve ends and becomes straight through the crossing. Compare and contrast with the B-10 picture commented on earlier. The fine point and blunt nose are marked but partly obscured by an over length rail. They show more clearly in the crossing to the top right, part of the single slip.
Spotted it yet? I have written B on the template above when it is in fact a C switch.
Stock rails 12.jpg


Back to the rail itself. Set mark aligned with the vice jaws. Bend gently to shape.
Stock rails 13.jpg


Rail viewed end on showing set bend.
Stock rails 14.jpg


The switch rail curve now needs to be added as may be seen toward the far end of the rail. (Depth of field, none.)
Stock rails 15.jpg
Stock rails 15.jpg (37.72 KiB) Viewed 1363 times


Place in position on the template and check alignment for accuracy.
Stock rails 16.jpg


Solder into place.
Stock rails 17.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Tue Feb 13, 2018 9:03 am

FITTING BRASS SLIDE CHAIRS.

Taking a slight step back, one needs to decide what type of, if any, Slide chairs to fit at this stage. If plastic slide chairs are to be fitted cosmetically later, then you can largely ignore what follows for now.
However if fitting Brass slide chairs there are two main types currently available for Bullhead pointwork.
The cast Brass pattern available from C&L. These are currently £10-00 per 8.
As I shall be fitting 4 cast slide chairs in this instance I have already soldered all the stock rail rivets.
This is the P4 version. There is also a OO/EM version E4CH 311A with a longer slide length to allow for a wider blade opening.
Note the casting lug still attached, particularly with the one to the right. This will need to be removed.
Stock rails 19.jpg


And the Bill Bedford etched pattern available from Eileen's Emporium.
Bill Bedford.jpg

I have found that these etchings can vary slightly, so make sure that the holes are big enough to fit over the rivet heads by opening them out sufficiently with a file or tapered broach whilst still in the fret if needs be. This is a lot easier than having to do each one individually after separation. This needle file has the same diameter at its max as the head of a rivet. I use the blue handled flush face cutters to remove them. Cut the thin edge of the fret at the side of the frame first to relieve as much strain as possible on the chairs whilst doing so. Then work along the outer edge cutting 2, 3 or 4 off at a time. Release by bending the remaining inner tab back and forth until it parts company. I have also found that these chairs have a tendency to bend easily where the hole is when removing from the fret. They can be flattened easily between the jaws of a smooth faced pair of pliers (the white handled ones pictured earlier). The chairs just need a light clean up with a smooth flat file to remove the cusp left by the etching process and any remaining holding tabs.

If using the etched chairs, then those joints where the slide chairs are to be fitted, plus at least one either side, to allow insertion, must be left unsoldered. Some pre-prepared slide chairs visible at bottom of picture,
DSCF0463.JPG


Fit all the slide chairs to one rail and solder into position. Start with one near the centre of the length to make sure the rail is in line with the rail on the template, then subdivide each gap until all are soldered. Make sure that the rail is firmly in contact with the rivet and slide chair down flat against the timber while the solder sets. Then repeat for the second stock rail.
DSCF0464.JPG


Where the Cast slide chairs are concerned, remove the lug with the face cutters and smooth off with a file.
Stock rails 20.jpg


Remove any rough spots from the underside of the chair with a smooth flat file. Any that are curved upward can be flattened first by placing the right way up on the vice and firmly pressing down on the upper face of the slide area with the screw driver. Then gently clamp upside down in the vice as shown as the next task is to split the chair in two using a piercing saw. Apologies for the picture quality. Taken on super macro setting so is super critical.
Stock rails 21.jpg


This is potentially one of those Ping moments as the saw blade breaks through.
Stock rails 22.jpg


With a round file hollow out the underside of the chair.
Stock rails 23.jpg


Remove the half chair and using a large pin vice (Eclipse No 123)
Stock rails 24.jpg


Gently cut back into the foot the chair with a fine 3 square file to make an easy fit around the foot of the rail.
Stock rails 25.jpg

Stock rails 26.jpg


Now for the inner half.
Hold the slide part of the chair in some small smooth jawed pliers as shown (not in the vice as the vice jaws will flatten the raised bolt heads) and proceed to file a half round cut out into it. This particular file is a Grobet & Vallorbe marked as a No 6. I also have one marked No 0, which gives much coarser cut that I use to start the cut off.
Stock rails 27.jpg

Stock rails 28.jpg

De-burr and clean up. Mind the bolt heads. A thumb nail between them and the file serves to protect them.
Stock rails 29.jpg
Stock rails 29.jpg (64.19 KiB) Viewed 1274 times


Place both haves of the chair in position and check for fit. It is at this juncture that one discovers a) how well positioned the rivets are and b) how good your soldering is as this can get in the way of the chairs. You may need to remove further material from the underside of the chair outer if the rivet projects too much here.
The trick when soldering. Apply a goodly amount of orange label flux to the joint area, making sure that the underside of the outer is well coated as well.
Apply the iron to the inside of the rail / chair joint and apply a tiny amount of solder from the outside to where the chair jaw and rail web meet. As the heat comes through the rail, some solder will melt and be drawn into the assembly holding it firmly together. Remove the iron and hold the rail firmly down (with screwdriver) whilst at the same time making sure that the inner half is firmly in contact with the rivet and in alignment with the timber and the outer is also down and against the rail web and all with just two hands. I actually use the end of the soldering iron bit to do any adjustments to the halves of the chair as one can gently prod them into position and then leave to cool. The important thing not to remove the downward pressure on the screwdriver until the solder has set.
Stock rails 30.jpg


Repeat for as many slide chairs as required. In this case 4.
Stock rails 31.jpg


The next job is to clean away the excess solder. For this I have modified a worn out square needle file by grinding down the end of the file on an oil stone to form a chisel bit. Beware of using a grinding wheel to do this as there is a chance of overheating the metal and losing the hardness. I first made this tool for cleaning out excess solder that found its way into the web of the rail, but it has since been found useful for other jobs such as the one we are about to do next.
Stock rails 32.jpg


Using a combination of the end of the file and the side teeth, gently remove any excess solder until a clean internal angle is achieved. Again remember to avoid filing the bolt heads. If any solder remains proud of the vertical rail face, there is a possibility that the switch blade will not close fully against it. If fitting more than two slide chairs to each rail, fit further ones singly from here on and clean off the excess solder as you go. This avoids having to work over too many existing slide chairs with the danger of removing bolt heads unobserved.
Stock rails 33.jpg


A closer look at the cleaned up slide chairs.
Stock rails 35.jpg


The rivets behind the slide chairs will also need to be dealt with in a similar manner until they no longer foul the foot of the switch rail.
Stock rails 36.jpg


The same goes for the etched slide chairs as fitted to the curved turnout.
The next bit to be tackled are the things that make it all work. The switch blades.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Tue Feb 13, 2018 10:53 pm

THE SWITCH BLADES 1.

Firstly cut and trim two over length pieces of rail as below.
Switches 1.jpg


Check the switch blade filing jig and make sure that it is set to the appropriate angle for the required switch type, in this case B.
Place both pieces of rail into the slots head outermost.
Switches 2.jpg


Do up screws finger tight and with the back of a fingernail push the rails in until they are flush with the end face of the jig.
Switches 3.jpg


Tighten both screws fully and check that nothing has moved.
Switches 4.jpg


Time for the big file. You need one with a safe edge.
Switches 5.jpg


Not like this.
Switches 6.jpg


Place the safe edge against the retaining block on the filing jig and proceed to remove any metal standing proud of the surface. You will find a point is reached when the resistance to movement rapidly decreases. You can also test if there is further material to remove by sliding the file from side to side. If you feel the file catch as it is moved back toward the rail, then the rail is still standing proud of the jig somewhere and requires further filing.
Switches 7.jpg


Once done turn the file over and repeat for the other rail.
Switches 8.jpg


This is what you should see.
Switches 9.jpg


And this.
Switches 10.jpg


Use a smaller file for a final rub down. No 2 cut.
Switches 11.jpg


What they look like when removed from the jig. The colours are artificial. They don't get that hot!
Switches 12.jpg


Examine visually for burrs.
Switches 13.jpg


and remove with fine file (draw file) before they find your fingers.
Switches 14.jpg

You can now throw the filing jig away metaphorically speaking as it will not be needed until making the next set of switches.
Last edited by Tony Wilkins on Wed Feb 14, 2018 1:17 pm, edited 1 time in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Wed Feb 14, 2018 9:06 am

THE SWITCHES BLADES 2.

What we need to do next is to remove the rest of the step on the inner face. Whilst this in itself would not be detrimental to the function of the finished blade, it is not prototypical and is going to get in the way of what we need to do shortly.
Switches 15.jpg


Select a small flat file with as squarer corner as you can find for the next bit and file away the step as best you can. Take care not to put sideways pressure on the file or you will remove material from the top of the foot as well as the inner face. Needle files with a safe edge don't seem to be that easy to find.
Switches 16.jpg


Like so.
Switches 17.jpg


Now choose a three square file with a sharp corner and remove any remaining material
Switches 18.jpg


until you end up with this. A good sharp internal corner.
Switches 19.jpg


Examine the face of the rail and look for the point where the rail regains its full profile. I have marked this on the picture.
Switches 20.jpg


Hold as shown with thumb on the end of the taper and gently bend the rail to transfer the angle from the front of the blade to the rear.
Switches 21.jpg


The running face should now be straight when viewed from the end.
Switches 22.jpg


Place the rail face down with the foot of the rail in the jaws and tighten to hold the rail in place. This is why you need a vice whose jaws have a good sharp square edge. This trick will not work otherwise.
Switches 23.jpg


Place a steel rule against the rail and mark the planing length. For a B switch this is 29.3mm. As the mark is over 1 mm wide this will only act as a guide when filing the back of the rail. The rule has also managed to move slightly between me marking the rail and taking the shot.
Switches 24.jpg


Slacken the vice slightly, place thumbnail firmly on rail web and re-tighten the vice with sufficient force to firmly hold the rail by the foot. With this vice you will need the Allen key, finger tight will not be enough. Do not be tempted to overdo this or the rail is likely to jump out of the jaws. Sufficient is enough. If you have trouble doing this, the most likely causes are, either the foot of the rail has a slight taper toward the edge or the vice jaws do not have a square enough edge.
Now take the No2 flat file and gently file slightly across and along the rail as shown (hold the file at a 30 to 45 degree angle relative to the rail) up to the mark
Switches 25.jpg


to produce an even taper. (A slightly hollow result is far better than a convex one, which can result in under gauge track.) Try to get the filed line between the end of the web cut and the web as near square as possible. In this case a bit more needs to be taken off the foot of the rail.
Switches 26.jpg


A word of caution here. With Steel rail as soon as the cut reaches the web as here, stop filing. Nickel Silver rail can take a bit more than this, but I have found that with the Steel rail if it gets too thin the end of the rail can suddenly buckle ruining the work you have just done.
Remove the rail from the vice, examine for burrs and gently remove with a fine file. Pay particular attention to the foot of the rail. With the No4 flat file, draw file the bottom corner to produce a radiused corner as this will help the switch rail seat better against the stock rail.
Switches 27.jpg

Switches 28.jpg
Last edited by Tony Wilkins on Sat Feb 17, 2018 5:26 pm, edited 1 time in total.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Wed Feb 14, 2018 2:32 pm

THE SWITCH BLADES 3.

To some it may seem as though we already have a perfectly acceptable switch blade, but there is still some way to go yet to produce the desirable ideal.

Real switch blades have the top edge planed over the same length as the horizontal planing. They are reduced in height by almost 3/4" at the tip, 10 thousands of an inch or 0.25mm in our scale. This ensures that the wheel tread does not begin to transfer weight onto the switch rail until it is some distance passed the tip of the switch blade in the facing direction. If the tip of the switch blade were left full height, it would actually stand slightly proud of the stock rail. A recipe for derailments. With the No2 flat file gently file back and forth along the rail head. The reducing thickness of the blade will ensure that progressively more material is removed from the tip than elsewhere. Take care not do overdo it.
Switches 29.jpg



I have placed the rule alongside in order to show the vertical taper more clearly. Aim for no more then this.
Switches 30.jpg


With the No4 file radius the top corner of the tip. N.B. the rail is up side down in this picture
Switches 31.jpg


With a small smooth file, file a taper along the top edge to thin the rail down to a fine edge at the tip. The taper angle should be 1 in 5 or approximately 12 degrees.
Switches 32.jpg


The effect is subtle and not easy to see in this picture.
Switches 33.jpg


With the smoothest file you have, draw file along the top inner edge to remove any last remaining burrs and radius any remaining square corners.
Switches 34.jpg

Switches 35.jpg



The vice used thus far is suitable for making A, B, C and D switch blades, just in the case of the D switches.
For E and F switches something bigger is required and I have a different vice with a special set of jaws just for that purpose
Switches 36.jpg


It is now a matter of repeating the process from the top of the second page (starting with the vice the opposite way round) for the second switch blade.
Starting so.
Switches 37.jpg


There may be a little further bending and straightening to do, but here are the finished pair.
Switches 38.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Fri Feb 16, 2018 12:01 pm

THE SWITCH BLADES 3.
Having fabricated the parts it now remains to fit them.
Put the straight switch / closure rail in position aligning the blade end. The tip of the blade should be on the leading edge of the slide area. (Some pre group companies had the tip of the switch nearer the centre of the chair.)
Switches 39.jpg


Mark the rail at the vee end where it needs to be cut, allow about 0.5mm for the insulation gap.
Switches 40.jpg


Cut to length and clean up the cut end. Check the fit of the blade is a snug fit against the stock rail (if not there may still be excess solder to remove) and the rail is truly straight. It may be found that the rail has not been correctly straightened at the end of the planing. Check also that the rivets are not standing proud of the surface of the slide chairs or the switch rail will catch on them.
Place in position and clamp with the hair grip. Make sure the ends of the clamp are above the foot of the rail. If the foot of the rail is trapped, the rail will twist leaving a gap at the running surface.
Switches 41.jpg


Use a track gauge to hold the other end of the rail and check the width of the gap. I use the thickness of a thumbnail as a handy gauge. (Rule of thumb?)
Switches 42.jpg


Solder this joint first the hold all in place. Then solder the first rivet at the blade end and begin with every 4th as before and then solder fully into place.
The Curved switch / closure rail will also need to be marked and cut to length but will also need to be pre-curved. This rail is only held by the clamp to demonstrate this.
Switches 43.jpg


It is vitally important that triangular track gauges are placed with the long side on the outer rail of curve, in this case the curved switch / closure rail, to ensure that you have gauge widening. (You will get gauge narrowing using it the other way round).
Working in a similar way to the first switch / closure rail, solder into place.
Switches 44.jpg


Here is a close up of the switch blade when fully held down showing clearly the gradual taper of the running surface from tip to full profile at the end of the planing length. I have noticed a tendency for switch blades to curve upwards during filing. Not really sure of the reason for this, possibly due to the metal stretching differentially during working. Whatever mechanism is used to operate the switches, some means of holding the tips down correctly needs to be incorporated.
Switches 45.jpg

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Fri Feb 16, 2018 7:02 pm

THE CHECK RAILS.
Check rails are needed to exclude the possibility of the wheel flange taking the wrong side of the vee in the facing direction.
For this size of crossing the check rail was normally 13' long. So cut two pieces of rail 52mm long and clean up the ends.
Switches 46.jpg


Form the flared ends in a similar way to how those on the wing rail were done. Insert about 12mm of the rail into the jaws.
Switches 47.jpg


Form first part of the bend.
Switches 48.jpg


Withdraw between 2 and 3mm and form second part of bend.
Switches 49.jpg


Withdraw a further 2 to 3mm and form third part of bend.
The distances are not critical, it is the overall effect that matters.
Switches 50.jpg


Some companies made just one single bend to do the job.
However you decide to make your bends, repeat the process for the remaining three ends.
Switches 51.jpg


Clean the underside of the rails. Check the accuracy of the flares against the template and make any adjustments you feel necessary. I generally fit the straight / main check rail first.
I then flux the rivets before finally placing the check rail in position ready to solder. I find that two Check rail gauges are beneficial to hold the rail correctly as shown.
Switches 52.jpg


I solder both end joints first followed by the centre one. Use the solder bit on the visible side of the check rail and feed the solder into the gap between the rails. Try to find the rivet head rather than the rail web if you can.
TIP: If you find you have problems getting the solder down between the rails to the rivet head due to its width, just squash the solder wire between the jaws of a smoothed face pair of pliers.
Switches 53.jpg


You can then remove the gauges and solder the remaining rivet joints.
Switches 54.jpg


Repeat for the second check rail. In some situations you may need to gently curve the centre section of the check rail to match any curve on the stock rail, but not in this case as the rail is straight throughout the crossing and for some distance either side of it.
Switches 55.jpg


Clean off any flux residue from the rail heads and anywhere else it shouldn’t be.

There are couple of things to watch out for. Place a finger on the far end of the vee rails and another on the beginning of the wing rail fronts. if you can rock the finished unit, it is not flat but hollow. To correct this, gently remelt the solder holding the vee tip to the wing rails (The A timber) whilst continuing to apply gentle downward pressure. You will be able to see the joint move when the solder melts. As soon as this occurs, remove the iron and continue to hold the rail down until the solder sets again.

If there is excess solder in the flangeway the easiest to deal with it is to remelt the solder and push it down to clear the flange depth with a crossing flangeway gauge being careful not to disturb the level of the crossing as above.
Your turnout is now complete as far as this exercise goes.

My next post will look at some aspects of prototype turnouts and hope to clarify some commonly misunderstood issues.

Tony Wilkins
Posts: 167
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Feb 17, 2018 7:12 pm

ADDENDUM.

These notes are for Bull head rail only.
First of all a bit more on crossing vees.
The types of chairs required for common crossings vary to suit the particular crossing angle and are not interchangeable. They are usually marked in some way to indicate what crossing angle they are. The number of chairs varies with the crossing angle. Here is a table showing what chairs are required for each standard angle listed. As you can see the number required increases as the crossing angle becomes more acute. I find it useful to know this information at times when working out the timbering arrangement beyond the crossing.
Crossing chairs.JPG

As noted below the column the A chair comes under the crossing nose.
The X, Y and Z chairs are placed towards the switch side of the crossing and the B, C, D etc away from the crossing under the vee rails.
It is not possible to use ordinary chairs until beyond the special chairs as the rails are too close together. Even then smaller bridge chairs may need to be used instead.

Prototype switches.
There are or rather were three types of switch design for bull head track in this country. Straight, Semi-curved and Curved. Here is a diagram showing the differences.
Switches005a.JPG

In Straight switches, the whole of the switch rail is straight up to the Fish plated joint.
Straight switches are specified by their length 9', 12', 15', 18', 24' and 30'. This is the distance from the tip of the switch to the heel where the heel clearance is 4 1/2". Note that this is NOT the overall length of the switch or tongue rail, which is greater than this.
With the Semi-curve switch, the planing length is straight but the remainder of the switch rail is curved to the switch radius (what I referred to as the switch rail radius in my construction section earlier). The planing length for an A switch is the same dimension as the 9' straight switch, B as 12' and so on.
Curved switches as their name implies are curved throughout at a constant radius and are very difficult to reproduce accurately in model form. Only the GWR and BR(WR) used them.

There are two ways of planing a switch rail known as Straight-cut and Under-cut.
There is apt to be confusion between the terms straight and straight-cut switches. The term Straight-cut refers to the way the switch is planed and nothing else. A straight-cut switch blade can be Straight, Semi-curved or Indeed curved as can an undercut one. Here is a picture of a straight-cut switch. The turnout itself is Semi-curved with spring switches.
Straight cut switch.jpg

Note how the reverse side of the switch blade nearest the camera is completely flat and the ends of the blades are quite thick.
The far switch rail sits in a joggle 3/8" deep. It is rather more subtle than might be thought. In scale it is only 0.125mm deep. If you can get the end of your switch blades that thin you are doing well.
Note also that the tip of the blade is only just lower than the stock rail yet the top surface of the switch rail shows no polish mark until about half way to the next timber. See also the questions thread page 3 for more pictures and info on Straight-cut switches and joggles courtesy of Martin Wynne.

Here for comparison is an under-cut switch.
Undercut switch.JPG

The tips of the blades are finer at the top but note the ridge on the reverse of the switch rail where it is thicker and cut to fit under the head of the stock rail. Here is diagram for clarity.
Switches006.JPG
Switches006.JPG (14.7 KiB) Viewed 794 times

There is no joggle in the stock rail their being a set in the far stock rail (not visible in this picture from this angle).
The Sole plate is clearly visible showing the end stops outside the slide chair to hold everything to gauge at this critical position.
This is a B switch again semi-curved spring switches. The way to tell this is to count the slide chairs. There are six chairs on the near rail with horizontal bolts holding the stock rail in place. Looking at the far rail, there appear to by eight slide chairs. In fact the far two are the first two block chairs. Note that their counterparts on the near stock rail use keys to hold it in place.

Here are some close ups of the straight-cut switch, the first showing the 2nd, 3rd and 4th block chair. Block chairs 3 and 4 hold the rails firmly by keys on the outside of the rail. Notice also the switch anchor between them preventing the switch rail from moving out of position.
Block chairs.jpg


Block chairs 1 and 2 hold the stock rail firmly by keys, but the switch rail is free to move on the short slide area cast into the chair. Note the cast in spacing blocks which hold the rail to gauge when the switch rail is in the closed position.
Block chairs 1.jpg


Slide chairs can also have spacer blocks, but in this case they have to be of a different design so they can be held in place by the nut and bolt.
Block chairs 2.jpg


Here is a table of components required for each type of switch for those who want to get it all right.
Switches001.JPG

and the diagram referred to showing how they are used. These can repay careful study as there is a lot of useful information here.
Switches002.JPG


Block chairs caused me no end of confusion. Photographs are rarely clear enough to be able to make out the detail and the British Railway Track book's description is misleading in that it begins 'A number of block chairs which fix the switch rails and stock rails in their correct relative positions' which I took to mean that they did not allow any movement period. It makes no apparent distinction between any of them apart from the following 'For the A, B, C, and D switches no key jaw is provided for the switch rail in the 1.P. and 2.P. chairs.' meaning the first two block chairs for each switch rail. Hardly obvious. For completeness I should mention that for E and F switches the 1.P. and 2.P. chairs have keys on the inside of the rail and do not allow the switch rail to move, because there is not room for the keys to go between the switch and stock rail.
For many years I made my turnout switches with movement only where the slide chairs were. This resulted in the switch blades not opening fully in the middle, yet no real issues have arisen because of this. It was only a chance conversation with Howard Bolton AKA(JFS) that led me to question this approach. I then decided to go and looked at the real thing. The pictures posted here were taken at Loughborough on the Great Central Railway and the close ups at Wirksworth on the Ecclesbourne Valley Railway.
I subsequently discovered that many of the turnouts had built for my layout Green Street had in fact fractured solder joints where the sliding block chairs should be and I have not resoldered them.

To be continued.


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