NFWEM57

Update Am busy updating my study / workshop so hence the quiet period - need a bit more desk space for FB track amongst other things. I have also started a paper on the subject, currently at 12 pages for the introduction, prototype, model theory and required tools stages. Did think of calling it the Wright Brothers guide to Flat Bottom Turnouts. Having attended a few club meetings of late, I am amazed at how many established modellers still think that FB modelling is not required because so much bullhead still exists on the prototype. Bit of Egyption mythology methinks..! de Nile. How do we attract younger modellers if we are focusing on track that was no longer used or replaced with new design over 50 years ago? New image rolling stock is everywhere, but not new image track. And for those who say that the track is not what people look at, why do C&L sell 2, 3 and 4 bolt chairs..!? It is, and will be, a difficult transition, but a necessary one. Patrick

I recently tried to remotor a Lima HST using the latest Railroad Bogie - but for EM and and metal tyres - it was a failure, could barely pull itself. The motor in the bogie is small in comparison to those in the Class 37/47 railroad bogies. I did convert a Class 37 using a full size CD motor (more space with EM wheels so a larger 12V motor can fit) and 2 Class 47 using modified railroad bogies with Alan Gibson wheels and all 3 worked reasonably well. I converted one of my LIma HSTs using a central drive motor two shaft driven bogies from the full fat Hornby HST - massive drawbar pull as you would expect; seperate thread on this My 3 remaining HSTs will be getting the same treatment. When converting to all metal tyres the big issue is weight. Provided the motor is powerful enough, there is around 70~75% conversion of weight to drawbar pull for wheels with traction tyres falling to 20~30% for all metal wheels. And it is weight on the driven bogie, not overall loco weight, that is important. So, the HST has 410g on two driven bogies and I measured a drawbar pull of 120g - around 29% conversion. For the Class 37, CD motor with Ultrascale wheels, only 40g drawbar pull was achieved whilst for the two Class 47, Railroad Motor with Alan Gibson wheels, the drawbar pull was 45g. The key is weight but too much weight overpowers the motor, too little reduces drawbar pull - for a a single driven boge aim for 200~250g over the bogie with an overall loco weight of 400~450g. It is a compromise. I might try 2 railroad bogies in my next conversion - requires a bit of engineering work on the railroad chassis where the dummy bogie sits but it will provide double the traction. For the surplus Lima bogies I will also try the double drive approach on some, again, a bit of engineering work on the original Lima chassis. Neither will use the cut and shut approach to chassis modification. Of course the simple answer might be to just buy the full fact versions of the class 37s and 47s, but I enjoy undertaking the conversions and it gives some reasonable models a new lease of life, indeed Hornby still use the Lima body shells. No issue with pick ups, all bogies have them, as all are DCC (ESU decoders) with bespoke (distributed) stay alives. Hope this helps. Of course, if you stick to using traction tyres, no problems, other than dirty track..!

Amazing. When I was train spotting as a kid in 1965-67 at Taunton I only saw one steam train - Evening Star hauling freight through at speed. Platform was packed with spotters Otherwise it was Hymeks, Warships, Westerns and Class 117s/121s with one spotting each of a Peak and Class 47 in the 3 years. Then I moved away further west where few trains ran.

Happy New Year..! Santa delivered the PWI book on FB switches and crossing and an interesting 'read' it has been. (The one issue is the binding which has already failed - so a 3 ring binder will be used to house it) From the history section it seems that vertical design flat bottom designs for turnouts came into being in 1967 and were by adopted by all regions by 1970, over half a century ago. A further major change came about in 1987 with the introduction of shallow depth switches which eliminated the need to plane the stock rails to accommodate the switch rails. These have been in use for nearly 40 years. A reduced height switch rail is used, asymmetrical in profile, which is placed on a raised slide plate; drawing is worth a thousand words - pandrol and other fastenings not shown for clarity. At the heel end of the switch rail there is a forged transition section which expands the switch rail back to full height, another drawing. Of course, for modelling, the rail profile is not available and such a transition is not possible. However, PECO code 60 rail can be used as a reduced height substitute and for the most of its length is planed, yet another drawing The transition section can be made by tapering the end of the full height closure rail and joining it to the code 60 switch rail with brass fishplates. For the slide chairs, the PECO ones are used with a 0.4mm thick pad paced over the existing pad which locks the stock rail in place and acts as a surface for the code 60 rail. Of course, suitable slide pads could be 3D printed but I am not there yet. The only other issue is suitable pandrol baseplates for the thinner base of the code 60 rail. Again, probably a 3d printing solution. The next task is to create a bespoke template in TEMPLOT to reflect the geometry of the modern turnouts; different sleeper/timber spacings and sizes. Had a few attempts but get double sleepers around the crossing V areas. Check rails are easy as they come in 4 standard sizes whilst the common crossings are pretty much a standard size (aside from the Vee rails) until the much larger turnouts sizes. As starter, I may construct a B8 turnout using a standard TEMPLOT FB template as a guide to see if the dual rail approach works. Of course, the choice of baseplates is very limited but perhaps something 3D printing can overcome. Another skill set to learn..! Patrick

Happy New Year Wayne, hope you have a fantastic 2024 and thank you for what you have delivered for us thus far.

Hi, EM gauge. The more I mull over using code 60 for the shallow depth asymmetric switch blades, the more it seems it might be a reasonable solution. I can modify the PECO slide baseplates by adding a 0.3~0.4mm thick additional pad on top which serves 2 purposes, it raised the slide pad area to match the code 60 rail and also locks in the stock rail. The prototype slide trackpads look like this (link to honour copyright): https://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.cdp-railsystems.com%2Ffileadmin%2Fmediamanager%2Frailsystems%2FProdukte%2FSlide-Chair-Plates-2.jpg&tbnid=lzLBQ-fgj8o_WM&vet=12ahUKEwjX4OmhpbKDAxUWVKQEHRgGDf8QMygAegQIARAy..i&imgrefurl=https%3A%2F%2Fwww.cdp-railsystems.com%2Fen%2Fproducts%2Fslide-chair-plates&docid=L-AinEnpetk_TM&w=2000&h=1333&q=shallow depth slide chair plate&ved=2ahUKEwjX4OmhpbKDAxUWVKQEHRgGDf8QMygAegQIARAy In use in practice: https://www.google.com/imgres?imgurl=https%3A%2F%2Fjournals.sagepub.com%2Fcms%2F10.1177%2F0954409715624723%2Fasset%2Fimages%2Flarge%2F10.1177_0954409715624723-fig3.jpeg&tbnid=l4vZbi2CGZp7_M&vet=12ahUKEwi0t5O3pbKDAxU6f6QEHS93CgUQMygAegUIARCZAQ..i&imgrefurl=https%3A%2F%2Fjournals.sagepub.com%2Fdoi%2F10.1177%2F0954409715624723&docid=VZ9ehqUWvQ4SAM&w=1700&h=1057&q=railway shallow depth slide baseplate&ved=2ahUKEwi0t5O3pbKDAxU6f6QEHS93CgUQMygAegUIARCZAQ I'll just add 0.3~0.4mm thick pad on the existing PECO slide chairs to take up the height difference. After the slide chairs the rail revert to full height code 82.

Thank you very much for sharing the information on C&L Code 82 and on mechanical wear and tolerances. I am aiming to scratch build, as best I can with the very limited components available, flat bottom turnouts as close to prototype as possible. Having researched a little more on the prototype it would be ideal if all the components to permit the scratch building of turnouts with shallow depth asymmetric switches rails - it would have saved a lot of filing...! But it seems I must implement something akin to BS113A Vertical or, more likely, its metric equivalent CEN56E1, with the available components. I doubt that reduced height asymmetric switch rail will ever be manufactured (even though it is in widespread use on the prototype) which somewhat negates manufacturing the relevant slide plates (which could easily be manufactured). I did mull over using Code 60 FB rail, suitably filed, as the asymmetric switch rail and Code 82 for the stock rails but there are no suitable slide baseplates to match although existing PECO ones could be modified. Perhaps another 'turnout in a bag' idea for C&L for shallow depth FB turnouts with very little filing required...! Ah well, a compromise (with a lot of milling or filing) it will have to be for me at least. On photography, another pastime of mine, I watched a friends business close down as the internet took hold. People would try (in the shop) before they bought (on line). I still support my remaining local photo stores by buying in person or via their on line portals.

Thank you. I guess I will have to see how the 2 types line up in practice for the model.

Thank you, and I appreciate and understand your comments about the retail business. My comments were not a criticism of either retailer, just an update to an earlier post in this thread regarding the dimensions of suitable FB rail. It would seem the only way to get the dimensions of rail is, as I have done, buy some and measure it...! I ruled out that using that option across the board because of the high cost, potential waste and because before I part with hard cash, I usually like to know exactly what I am buying to avoid disappointment. I guess I am therefore one of those annoying people who, for good reason, wants to discuss things before getting their wallet out..! Thus far on this FB voyage of discovery I have had to purchase most components blind and although there has been some waste, fortunately it is not as much as it could have been; eBay might allow me to recover some of that wasted outlay. Hopefully, what I share here will contribute in some small way to allow others to make a more informed decision on going down the FB path and/or what to purchase. At the moment there is precious little information out there; that i could find at least.

Well, Santa has delivered the PWI book on Flat Bottom Rail Switches and Crossing and it is very enlightening. The UK seemingly went through a period of continuous development around the mid 1960s to 1970s before largely settling on what we have now. Thankfully the switch and crossing designs are vertical which means the only available baseplates are suitable. Appendix 10 of the volume has all the necessary detail of vertical rail design switches and crossings to allow specific templates to be made including setting out detail, timbering and baseplates required. The challenge will be removing the material from the rail for switch blades and crossings. The basic crossings Vs are simpler than the switch blades but the wing and check rails add to the complexity. For the switch blades I might need to make a jig to curve and hold the rail before it is filed or milled to the required planing radius. Something similar will be required for the wing and check rails. EMGS rail will be used as it is the closest in size to the prototype. No feedback from Marcway or C&L on their rail dimensions. One final design consideration is the transition from the vertical of the turnout to 1:20 inclination of plain track which is undertaken within one sleeper spacing on the prototype, but obviously this affects the gauge. Might need to put a slight twist in the various rails before turnout assembly and gauge accordingly. Another issue is is the connection of FB rail on a mainline turnout to bullhead rail on a siding or branch line. Brass fishplates soldered in place might be a solution. First tasks before the attempt at at turnout is a modified set of 3 point and roller gauges followed by the design of a filing jig for switch blades and crossing Vs. Conveniently, check rails come in just 2 standard sizes..!

Flat Bottom C&L planed blades?

Alas, I model in EM so not a lot of good..! So for EM /P4 Ultrascale is the only option for wheel sets with gears on the back of the wheel. However, for my OO gauge refurb and sell they will be ideal. Thanks for the heads up.

You do..! You get around 65~75% conversion of weight to traction (pulling power) with traction tyres and only 20~25% without. I recently converted a Lima Class 37 using a full size CD motor, an Ultrascale EM gauge wheelset and added 50g addition weight. The EM gauge wheelset allows a larger 12V CD motor to be fitted. post conversion, the loco hauled 6 Mainline Mk1s with ease (total weight 900g) at a scale 90 mph. For Ringfield type conversions, I measure the weight on each bogie and try to shift weight toward the power bogie end rather than just add more weight overall - lead sheet works well. Prior to conversion there was 205g on the power bogie and 240g after with the same weight on the dummy bogie of around 200g. Pulling power reduced from around 135g (65%) to 45g (19%) as measured using a spring gauge. Of course, there are not many option for wheel sets for Ringfield drives, just Ultrascale I think.

I model in EM gauge and recently tried to convert a Lima HST using a Hornby Railroad Power Bogie - tiny motor and without traction tyres, could only just pull itself. Undertook the same for a Lima Class 37 using a Hornby Railroad bogie - bigger motor and plenty of pull without traction tyres and hauled 6 coaches with ease. I don't think there are too many sizes of motor as the Railroad Class 47 bogies are the same as the Class 37 ones. The motor in the Class 43 HST bogie is quite small, possibly deliberately to steer buyers towards the full fat HST that Hornby also make. Being small, adding weight to gain traction overwhelmed the motor so in the end I added the full fat bogies and central drive motor to my Lima HSTs and sold on the original Lima bogies. Overall cost was far less than buying a Hornby full fat HST..! The only way to find out I guess is to measure the motor you have in the 2bil and ask on this forum. Provide a side on image with a ruler in the shot and people could give you feedback on sizes of other bogies; happy to do so for Class 37 and Class 47 bogies.

A video paints a thousand words... This is a converted 5MT with Alan Gibson wheels running through B7 turnouts and the 1:7 double slip from British Finescale.

Update The last few (available) components have arrived I think I have all I need to scratch build a simple flat bottom rail turnout. The latest volume on Flat Bottom Rail turnouts (by the PWI) has also arrived to shed some much needed light on modern practices, but only on and after 25th December..!! I will have to find a solution to distance blocks which are fitted after the moving sections of the switch rails between the stock rails and switch rails where there is no space for L1 and S1 style baseplates. Similar blocks will be required at the crossing V to maintain distance between the crossing Vs and wing rails; 1mm high x 2mm wide rectangular black plastic rod will suffice cut to length as required to fill the gap. A period of research before beginning I think. Nothing i require on my planned layout in flat bottom rail is below C8, and that is a crossover, so It might be a much simpler D12 as a first attempt; lead around 30m so around 400mm (16") toe to nose and a natural turnout with 5m (16ft) radius for both switch and turnout.

Hi, Thanks for the comments and images you have posted to this thread, I assume it was for me..! The layout looks impressive. My layout will not be built until after a post retirement relocation in around 18 months time so I am busy making up various sections of the layout where there is point work in the meantime. I have settled on the PECO baseplates with EMGS flat bottom rail and wooden sleepers/timbers for the turnouts and the ExactoScale concrete bases for plain track. The main lines will be flat bottom, the branch lines will be bullhead. Tried looking up the P4 Track Company, nothing found but the odd link to ExactoScale. Yes, there is a lot of base material to remove on flat bottom rail but I intend to mill the rail to near size and hand finish. I will clearly need to design and make a few jigs. I have British Railway Track - Design Construction & Maintenance (1979) 5th Edition and Santa is bringing me the latest textbooks on track, flat bottom turnouts and bullhead turnouts from the PWI so i should be able to create some meaningful templates. I live near Waterlooville so I may be in contact in the via a PM in the new year. Patrick

Ah, apologies, forgot to include A7, B9 and B10 but not A6 where switch radius is 482ft and turnout radius is 326 ft.

It is where the switch radius is equal or very close to the turnout radius and they are called natural turnouts. A8, B8, C10, D12, E16 and F20 are the ones according to the 2mm Scale Associations excellent book on Track.

Hi, There are many experts on this forum who will give you sage advice, I am not one of them.! However, from my copy of the 5th edition of the British Railway Track - Design Construction and Maintenance, table 16 indicates the following ranges for bullhead rail: A4 to A8 (but not GWR) with a turnout radius of circa 520mm (A4) to 1,928mm (A8) B6 to B11 with a turnout radius of circa 1,248mm (B6) to 2,452mm (B11) C7 to C14 with a turnout radius of circa 1,664mm (C7) to 3,840mm (C14) D8 to D16 E10 to E16 (but not GWR) F16 to F20 (but not GWR) 30ft - 13 to 20 (GWR only) Tables 17 to 29 also gives details for flat bottom rail for a range of switches from A to G On the other questions (side play etc) I have no idea, but the experts will hopefully advise you.

Solution to tight fit of EMGS Code 83 rail in ExactoScale Concrete Track Base Curious as to why the rail was a tight fit, I tapered the width of the base of the rail to see what dimension slid easily into the track base. At around 1.80mm width, the rail slides into the track base with ease; just 0.01mm difference. On a longer piece of rail, I ran a piece of fine wet and dry along both edges of the base and after a few iterations found the entire rail slid easily through a section of track base. A little bit of extra work but at least you get a length of concrete track with almost scale rail assembled in just a few minutes. It would be prudent to do the same on any rail being used for turnouts to avoid stressing the baseplates. The cost of 1m of EM gauge flat bottom track on concrete sleepers is approximately £8.20 from the EMGS. The track base is also available in OO and P4 from the EMGS (and others) as is the rail. Patrick

C&L error corrected, too may 82s and 83s..! I have discovered that code 82 or 83 indicates nothing about the size of the rail other than its overall height..! Nothing about rail head width, base width or base thickness. Is it any wonder we are all confused and meaningful progress on FB turnouts has stalled..! According to a previous post elsewhere some time ago, (https://www.scalefour.org/forum/viewtopic.php?t=7339) C&L code 82 had a head width of 0.8mm, not 0.92mm, and so is undersize by 0.12mm and not prototypical; have asked C&L what size their current code 82 rail is. Peco code 83 has a head width of 0.79mm. EMGS code 83 has a head width of 0.94mm; oversize by 0.02mm. Amazingly, Karlgarin 82 has a head width of 1.12mm but that rail is for a different solution..! None of this critical detail is ever listed on most UK websites, just the overall rail height which is about as much use as a chocolate fireguard..! Look at a German website and they provide the key detail, even for PECO code 83. That is why I purchased the various bits in small quantities to find out the facts and share here. We need to know the rail head width, the base width and the base thickness (as it might be the correct width but too fat to slide into the baseplates). We need to know the maximum rail base width height for various baseplates not have to discover - at cost - by trial and error. Finally, EMGS code 83 is in fact 0.082", as measured..! Rail specific dimensions measured or found to date are as follows with prototype (blue), measured (green), on line search (yellow), unknown (red): Dimensions have been requested for C&L and Marcway rail. Patrick

An update. Various baseplates and sleepers have arrived along with rail from 2 sources. Rail One from PECO, code 83, and one from EMGS, again code 83. PECO unsuitable, way undersize, but EMGS almost spot on wrt prototype, slightly oversize head (+0.02mm) and undersize foot (-0.02mm) so will require the slightest of adjustments to a spare set of roller gauges (DCC Concepts) but 3 point gauges are just about fine (DCC Concepts). Alan Gibson check rail gauge is also fine. The base thickness is 0.41mm, the same as PECO code 83. Still waiting for rail from one more vendor and have requested dimensions of code 82 from C&L and code 75 flat bottom from Marcway. Track Base The PECO Code 83 rattles around in the baseplates so no good. The EMGS Code 83 rail is a very tight fit in the ExactoScale track base but it does fit - just. It might be a struggle to make up long lengths but see solution in later post. Sleepers are 1.83mm thick at the edge and 1.24mm in the centre. Rail head to bottom of sleeper is 4mm; the same as bullhead flexi-track. Medium grey in colour. Sleepers are 32.3mm long by 3.1mm wide top and 3.3mm bottom. The rails have the correct 1:20 incline and measure 18.2mm apart at the top of the railhead. Sleepers PECO concrete sleepers are a cream colour, like a milky bar, 1.8mm thick at the edges and 1.5mm in the centre. The sleeper length is 31.7mm long by 3.5mm wide. Sleepers are 32.3mm long by 3mm wide top and 3.6mm bottom. C&L Sleepers are a lighter grey than the track base, are 33.65 wide and 3.35mm wide with next to no taper from top to bottom. 1.55mm thick at the ends and 1.25mm in the centre. PECO timber sleepers for turnout construction are 88mm long by 3.93 wide (scale 11.75 inches wide). Thickness 1.23mm Baseplates In all cases, as with bullhead rail, a taper must be put on the end of the rail base to ensure the baseplates slide on easily without damage. All the baseplates fitted the EMGS rail and were easier to install whilst still on the sprue. PECO baseplates as provided with PECO concrete sleepers. Might resemble the early BR baseplates. Railhead to bottom of baseplate 2.75mm. (PECO sleeper, 4.55mm overall. C&L Sleeper, 4.3mm overall, PECO turnout timbers 3.98mm overall) PECO pandrol baseplates, appear slightly oversize but acceptable detail. Railhead to bottom of baseplate 2.65mm. (PECO sleeper, 4.45mm overall. C&L Sleeper, 4.2mm overall, PECO turnout timbers 3.88mm overall) C&L baseplates, smaller than the PECO baseplate and detail smaller than PECO Railhead to bottom of baseplate 2.65mm. (PECO sleeper, 4.45mm overall. C&L Sleeper, 4.2mm overall, PECO turnout timbers 3.88mm overall) Image below, PECO Pandrol top, C&L middle, PECO basic bottom if making up plain track using the baseplates, sleepers and rail, there would be no 1:20 incline. So, the baseplates are only of use in turnouts where the FB rails are vertical. I'll update when more parts arrive and then commence a turnout in the new year as the festive season, with its many distractions, is now upon us...! I also need to collect more information re baseplates on FB turnouts. Patrick

Thank you. Martin Wynne told me the same and when I checked the specification, although the correct height, the head and base are too wide, 22% and 11% oversize respectively.

Interesting thread and the issue of code 82 and 83 rail head size continues..! My aim is to scratch build FB turnouts in EM gauge and I am trying to source code 75 or code 82 FB rail with the correct rail head width. Not easy. The PECO code 83 is 15% undersize at 0.79mm. Just waiting on code 82 and code 83 rail from 2 other sources to check dimensions. If the C&L code 82 rail head is still 0.67mm then that is a non starter. Marcway have code 75 FB listed but no dimensions but, if the head size is as you have listed and the foot is the correct size, bingo, problem largely solved.