Templot Club Archive 2007-2020
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posted: 24 Sep 2008 02:25 from: phileakins
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Not having the the right volumes in my library (someone out-bid me! ) - can anyone tell me the minimum chainages for curves/turnouts for both running lines and sidings applicable pre-group (c 1915) lines?Sorry, I know it's a very broad question, but from an OS survey it looks like 4 to 4.5ch for running lines and 3ch (perhaps a little less) for sidings. Confirmation would be nice though! Thanks Phil |
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posted: 26 Sep 2008 03:47 from: phileakins
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Ummm ... No-one got a view? Phil |
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posted: 26 Sep 2008 04:35 from: Martin Wynne
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phileakins wrote: Ummm ... No-one got a view?Hi Phil, I don't think any such fixed limits exist. Everything depends on what rolling stock you expect to run on it, and at what speed. Sharp curves have gauge-widening, continuous check rails and severe speed restrictions. Continuous check rails are required on curves below 10 chains radius. Gauge widening is 1/4" on curves between 10 and 7 chains radius, 1/2" on curves between 7 and 5.1/2 chains radius, and the maximum 3/4" on curves below 5.1/2 chains. These features are quite often found within station limits, but it would be very unusual to have such sharp curves on running lines in open country. An A4 turnout has a radius of 130ft, which is less than 2 chains. That would be regarded as acceptable in a goods yard, but only for short 4-coupled shunting locos. Industrial turnouts can go down to 1:2 angle, with a radius of only 40ft, i.e. well below 1 chain radius. But only the smallest shunting locos (or horses?) would be used on those. regards, Martin. |
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posted: 26 Sep 2008 05:42 from: Noel Adams
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phileakins wrote: Ummm ... No-one got a view?Phil, I'm no expert, but in Iain Rice's book "Designs for Urban Layouts" he says that he had checked on minimum curve radius for a range of locos (although from a later period) and came up with a figure of four and a half chains absolute "at dead slow speed", with six chains as a normal service figure. Special cases - lines limited to SWB stock and specially designed engines - could go down to around two chains (LMS Fowler dock tank or similar). Is this of any assistance? Cheers Noel |
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posted: 26 Sep 2008 16:03 from: phileakins
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Hi Martin & Noel Thank you both, that helps a lot as it shows that the OS cartographer wasn't just making it up. Those curves are awful sharp and photo's do show check rails were used throughout. Martin, can I make a plea for a future version to have the ability to apply check rails to plain track? Thanks again. Phil |
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| Last edited on 26 Sep 2008 16:04 by phileakins |
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posted: 26 Sep 2008 16:50 from: Martin Wynne
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phileakins wrote:Martin, can I make a plea for a future version to have the ability to apply check rails to plain track?Hi Phil, You can do that with partial templates. Just remove everything from a turnout except the main-side check rail, extend its length, and then align it over the plain track. Here's a bit of scruffy Jing video showing that: http://screencast.com/t/hRWvua7F regards, Martin. |
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posted: 26 Sep 2008 19:03 from: phileakins
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Thanks Martin. That video is very useful. Can I use the same technique to put check rails on both running rails? Sorry, I'm being lazy and asking instead of trying things out for myself! Phil |
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posted: 26 Sep 2008 19:44 from: Martin Wynne
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phileakins wrote: Can I use the same technique to put check rails on both running rails? Sorry, I'm being lazy and asking instead of trying things out for myself!Sure. After doing store & background on the first check rail, press CTRL+X (that's template > invert handing menu item). Change the length or position to whatever you want. Then store it again. Wait until the underlying plain track is curved and finalised in position before doing any of this of course. Otherwise you will have to do it all over again. Just a p.s. to this method -- first extend the original turnout (using F4) until it's long enough to contain the extended check rail. Otherwise you will not get the full length of the check rail or the end flare section. There is an alternative method mentioned in the Help for getting the check rails and plain track in a single curvable template -- add approach track to a turnout (F3), increase the working length of one or both the check rails sufficiently to extend back into the approach, put the peg at CTRL-1 and then do > snap to peg menu item. The disadvantage with this method is that you have to do each end of the check rail(s) as separate templates to get the end flares, and you can't use the roll rails functions on the templates because they are still turnout templates. regards, Martin. |
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posted: 27 Sep 2008 02:43 from: John Lewis
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Martin Wynne wrote:Industrial turnouts can go down to 1:2 angle, with a radius of only 40ft, i.e. well below 1 chain radius. But only the smallest shunting locos (or horses?) would be used on those. Or pinchbars? John |
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posted: 23 Oct 2008 02:22 from: phileakins
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Hi All Following Martin's video I've sorted out how to put continuous check rails on both rails of a a 4 chain-ish constant radius curve, I thought I'd see how to deal with a crossover. I can add the check rails I want by extending check and wing rails on the turnout side of a turnout, and adding continuous check rails on the main road using Martin's method, using a bit of imagination to 'gap' the flangeway at the wing rails. What I can't see is how to 'check' the closure rail on the turnout side. I've attached the box file just in case! Thanks. Phil PS Extending check rails using the mouse would be brilliant!!! |
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| Attachment: attach_369_563_check_rail_curves_do_08_10_22_2037_54.box 212 | |||
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posted: 23 Oct 2008 16:04 from: Peter_Hirons
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Just curious - why do you need check rails on the outside rail? I have only ever seen them on the inside rail on curves and I don't see what function they would serve. I have seen check rails on both over bridges, but that is for a different purpose. Peter |
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posted: 23 Oct 2008 20:27 from: Phil O
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Hi Phil If you use check rails on both rails the flanges will bind or worse the flange will ride up on one check and cause a derailment. The exception is that track inlaid in a surface such as a road etc may have a check both sides but the outer check is usually well inside the outer rail to prevent said binding or derailment. This was not applied at one place on a realigned section of rail in HM dockyard which caused a double bogie vehicle to derail when being propelled on the trailling bogie and derailed the other bogie when they tried to pull it back on. Cheers Phil. |
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posted: 23 Oct 2008 22:32 from: phileakins
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The trackwork has one functional checkrail on the inside rail of the curve as it is less than 10 chains radius (ie about 180 inches in 7mm scale). The track is also tramwayed which is why there is a 'check' rail inside the outer rail of the curve. I'll bear what you said in mind Phil - thanks. Phil |
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