Templot Club Archive 2007-2020
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posted: 13 Jan 2011 11:52 from: M Wright click the date to link to this post click member name to view archived images |
Hi, I am new to this forum but in real life am a professional model maker. Over the last couple of years I have become increasingly interested in producing a model of a rail system near to where I grew up. This was a North British line often called the Gifford and Garvald. The part that interested me was a stretch through the East Lothian Coalfield. I wanted a diorama type layout so that suggested a model in N scale. I made a start in 2mmFS but decided when Bachmann announced a 2MT in their Farish range that this was a better route to go along since then the whole model might get finished! However since the change over in direction and building a trial shunting layout using Peco "finescale" track, a Farish Austerity tank and a few coal trucks I have found some problems. 1)The track is hard to use if you wish it to comply with a photo of a scene. The flangeways are extremely generous and they and other aspects of the turnout do not conform to any published standard. 2) The current coupling system of commercial N is crude to say the least and spoils any scene. At this point I found Templot so I thought my first problem was solved. But no, Farish themselves do not seem to engineer their current chassis to any published standard. Obviously you can only build track to a consistent standard. For example on putting the Vernier to stock I found that in 3 wagons the back to back varied from 7.21mm to 7.47mm and on the Austerity the range was from 7.2mm to 7.35mm . As all the wheels seem to be to NMRA S-4.2 standards why is the back to back not? It should be 7.65mm. So I made an accurate gauge and on the Mill a small puller and reset a wagon's wheels to the NMRA standard without problem. I will now try the loco. If this all suceeds I can design the layout and the flangeways can be 0.71mm a great improvement in appearance, and the new Farish wheels have a small enough flange to run on Code 40 rail. Anyboby else found similar problems/solutions? Couplings are going to be Spratt and Winkle they seem to work and again on the latest stock seem quick to fit. |
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posted: 13 Jan 2011 12:31 from: Martin Wynne
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Hi, Have a look at David Renshaw's "Waton" in N gauge, which recently won the RMweb 2010 Challenge competition and also the trackwork prize. It takes some believing that this is N gauge: trackside2_19Oct10.jpg  © David Renshaw Summary: http://www.rmweb.co.uk/community/index.php/topic/25273-waton/ Full topic (13 pages): http://www.rmweb.co.uk/community/index.php/topic/4400-waton/ If you make the flangeway 0.71mm on 9mm track gauge the check span will be 7.58mm. If the back-to-back is 7.65mm, that will give you a check clearance of only 0.07mm, which seems a bit tight for commercial wheels. regards, Martin. |
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posted: 13 Jan 2011 14:03 from: Jim Guthrie
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If you are worried about the coarse nature of N scale track standards then you might consider modelling to 2mm scale standards. The 2mm Association provides wheels that can be used with UK N scale products and they have a very good range of track making products. The prices of their products are also very attractive and could balance the cost of membership of the Association. Another option is to model in FS160. This standard uses 2mm FS standards but at the N scale gauge of 9mm. This means that you can still use ready made 9mm gauge plain track but you have to build your own pointwork to the 2mm FS standards. You also have to use the 2mm Association wheelsets pushed in to 9mm gauge. Jim. |
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posted: 13 Jan 2011 19:24 from: M Wright click the date to link to this post click member name to view archived images |
Hi, thank you Martin for your interesting reply. You have worried me, Looking at the NMRA standards (S- 4.2)again they detail the span as 7.49mm with the 0.71 flangeway and I assume this goes with the wheel standard S- 3.2 which gives the target back to back as 7.65mm. I had possibly wrongly(?) assumed these dimentions were achievable. Have I made a mistake? If your figures are from experience and what is actually achievable clearly it is hopeless to expect to get my stock with a clearance of only 0.07 through any crossing. Back to the drawing board. Your illustration of N gauge track is super, where can I find more info on this modellers work? |
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posted: 13 Jan 2011 19:30 from: Nigel Brown click the date to link to this post click member name to view archived images |
Just for my own interest, are the wheel standards for the latest Bachmann N gauge locomotives any finer than the older Farish stuff? They certainly look better. And are they usable with, or at least adaptable to, 2mmFS standards? Recently bought an example of the very nice Bachmann Class 24, and see that the 2mm Scale Assocition offer drop-in wheel sets to 2mmFS standards, so at least in that area can see no obvious problem. Just wondering what applies to the better steam locomotives. Re couplings, keep on hearing rumours about one of the main N manufacturers developing a much neater unit, which would certainly be a good thing. Any ideas? Nigel |
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posted: 13 Jan 2011 19:36 from: M Wright click the date to link to this post click member name to view archived images |
Hi, thanks for your reply. I have only limited time to produce this layout. It is just r and r for me and not part of earning money. I had started in 2mmFS but it takes too long. I thought that I could save time by using some of the new N models appearing. They are as good as anything I could make, indeed having taken one out of a box and run it, better, in that no time is wasted perfecting the mechanism. However the disappointment is with these models is the lack of quality control on such a basic thing as back to back. Thinking about the "reviews" in the railway press this item is never checked or measured. If I can move the wheels and run the models on more realistic track I am happier than buying the model and then stripping it to change all the wheelsets. Not only is the obvious second cost but a lot of time is going to be taken. regards Malcolm. |
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posted: 13 Jan 2011 21:24 from: Martin Wynne
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M Wright wrote: You have worried me, Looking at the NMRA standards (S- 4.2)again they detail the span as 7.49mm with the 0.71 flangeway and I assume this goes with the wheel standard S- 3.2 which gives the target back to back as 7.65mm.Hi Malcolm, The NMRA standards were changed recently to target dimensions (instead of the former max and min figures), and since then it has been quite difficult to make sense of them. Some of it just doesn't add up. The track gauge for N gauge is given as 9.02mm target, and the check gauge as 8.26mm target. That makes the nominal flangeway at the check rail 0.76mm. Those appear to be direct conversions from imperial dimensions. To be sensible I would change that to 9.0mm and 8.25mm, giving a check flangeway of 0.75mm -- and easily remembered dimensions. The check span is given as 7.49mm target, so subtracting that from the 8.26mm target check gauge gives a nominal flangeway at the crossing of 0.77mm. Again to be sensible and for symmetry I would change that to 7.5mm span and 0.75mm crossing flangeway. With the back-to-back at 7.65mm target, that gives you a more sensible running span clearance of 0.15mm. But the NMRA spec says 0.71mm target for the flangeway dimension. I don't understand where that comes from or how you could build to that and still meet the other target dimensions. In fact you can't. Answers on a postcard to NMRA.  Your illustration of N gauge track is super, where can I find more info on this modellers work?I gave 2 links below the picture. Here they are again, and a third one: http://www.rmweb.co.uk/community/index.php/topic/25273-waton/ http://www.rmweb.co.uk/community/index.php/topic/4400-waton/ http://eldavos.awardspace.com/cramdin_yard regards, Martin. |
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posted: 14 Jan 2011 12:26 from: M Wright click the date to link to this post click member name to view archived images |
Hi, thanks for this reply. Do you think that the running span clearance of 0.15mm is feasible in operation? If your experience says yes then the ammendments to the NMRA dimentions you suggest I will try. Thanks for the third site reference. Water Orton's track appearance and his philosophy with regards to the stock is exactly what I would hope to emulate. Thank you for your interest and help. regards, Malcolm. |
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posted: 14 Jan 2011 12:59 from: M Wright click the date to link to this post click member name to view archived images |
Hi, Nigel, I have only recently purchased any Bachmann Farish stock so have no examples of "first generation" stock. What attracted me to this recent stuff is it looked much more like the real thing. Body sizes were right (I want to model mid-fifties so steam), shapes were right and the level of detail good. Most importantly wheels see through and looked fine. The pastry cutter flanges were gone. I have measured an Austerity tank and a coal wagon for you. Loco wheels, overall width 2.25mm, thread width at flange root 1.46mm, flange thickness 0.58mm, flange depth 0.58mm. The wagon wheel is similar except the overall thickness of the wheel is 2.0 mm. So the flanges are about 23 thou thick and deep. They look good. The only let down is the back to backs they vary a bit . see above. Regards Malcolm |
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posted: 14 Jan 2011 13:09 from: Martin Wynne
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M Wright wrote: Do you think that the running span clearance of 0.15mm is feasible in operation? If your experience says yes then the amendments to the NMRA dimensions you suggest I will try.Hi Malcolm, I have no direct experience of N gauge/2mm scale. However in 4mm scale (and narrow-gauge variants) the usual assumption is 0.1mm span clearance minimum, and 0.2mm desirable minimum, so your 0.15mm dimension seems feasible for the smaller scale. Of course a lot depends on how true the wheels are running on the axles, and your intended minimum radius. In practice the back-to-back should be quoted as a minimum, not a target. In my opinion the NMRA have made a complete dog's breakfast of the dimensioning with the new methods. More important than BB is the BEF setting (called "wheel check gauge" by NMRA, dimension K). Again this should be quoted as a maximum, not a target. I suggest you set your wheels to BEF 8.25mm max, which in many cases may give a greater back-to-back than 7.65mm, and hence more span clearance. In other words when setting wheels on an axle, BEF gives you the maximum separation and BB gives you the minimum separation. In summary I suggest: TG track gauge: 9.0mm MIN. CG check gauge: 8.25mm MIN. CS check span: 7.5mm MAX. CF crossing flangeway gap 0.75mm MIN. BB wheels back to back: 7.65mm MIN. BEF wheels back to effective flange: 8.25mm MAX. In addition the crossing flangeway gap must not be more than half the wheel width (or wheel width minus blunt nose width, if you are using prototypical blunt nose vees). regards, Martin. |
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posted: 14 Jan 2011 15:06 from: M Wright click the date to link to this post click member name to view archived images |
Martin. thanks for latest message. You have set the information out very clearly for me. I will set about making a set of track gauges to these dimentions and report how i get on. Regards, Malcolm | ||
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posted: 14 Jan 2011 19:32 from: Nigel Brown click the date to link to this post click member name to view archived images |
Malcolm. Thanks for the info. Was just wondering what would happen if you whacked a modern Bachmann Farish steam loco on a bit of 2mm scale track. Looking at the 2mmFS standards the most obvious problem from your measurements would be that the wheel flanges appear to be a bit too thick to go through the flangeways, which I suppose is what one might have expected. Cheers, Nigel | ||
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