Point radius?

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pandsrowe
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Point radius?

Post by pandsrowe » Fri Aug 16, 2019 10:04 am

With all the discussions that have been taking place recently on track gauges and the like, it has brought to my attention that a lot of people refer to radii as R1, R2 etc. Excuse my ignorance but can anyone tell me what these radii actually are?
Phil

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Re: Point radius?

Post by GTB » Fri Aug 16, 2019 11:29 am

pandsrowe wrote:
Fri Aug 16, 2019 10:04 am
With all the discussions that have been taking place recently on track gauges and the like, it has brought to my attention that a lot of people refer to radii as R1, R2 etc. Excuse my ignorance but can anyone tell me what these radii actually are?
The use of R1, R2, R3 and R5 to describe the curvature of set track originated with LGB and is now used by other G scale manufacturers to describe their set track curves. To confuse english speakers, the catalog quotes the diameter of the curves in mm, which is quoted as centre to centre and also outer rail to outer rail for some reason.......

https://www.lgb.com/fileadmin/media/lgb ... m-Info.pdf

R1 is a radius of 600mm
R2 is a radius of 780mm
R3 is a radius of 1195mm
R5 is a radius of 2320mm

For the non-metricated they are roughly equivalent to 2’, 2’6”, 4’ and 7’6” radius curves.

I own exactly four pieces of LGB track. Two double straights and two R3 curves, that I use on the workbench to test that new models will negotiate a minimum 4’ radius reverse curve, which is my design standard.

Regards,
Graeme

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Re: Point radius?

Post by idlemarvel » Fri Aug 16, 2019 12:42 pm

Graeme is correct as far as LGB is concerned, however other manufacturers of code 332 track use the same names for different radii.
R1 tends to be universal (600mm) but for example PIKO R3 is 922mm not 1195mm. The other manufacturers (Train-Line 45, Aristo-Craft, there may be others) have their own differences. Someone on gscalecentral attempted to produce a table of all these set track curves, I'll see if I can find a link.
Dave Miller
currently building the 5" gauge Circle Line

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Re: Point radius?

Post by DonW » Fri Aug 16, 2019 1:08 pm

THe Peco G scale turnout is advertised as medium radius 1219mm

Don

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Re: Point radius?

Post by Oily Rag » Fri Aug 16, 2019 7:52 pm

I think part of the confusion lies in the metric versus imperial schools. 45MM gauge is used much more widely in North America with a number of large manufacturers like USA Trains, (Aristo, Polks Hobbies pulled the plug a while ago). The conversions, if that is what they are are not directly the same but usually pretty close. The original system as I laid out elsewhere this week was thought out and designed by Ernst Paul Lehman Patentwerks GMBH and was released to the public in February 1968, (the Lehman Gross Bahn--- i.e Lehman Big Train). It would seem that North America very quickly took it all to heart but used Imperial dimensioning and sizes (plus two different scales).

There may be differences in basic dimensions but I have a number of manufacturers in my colllection of track and I have found that all are compatible. At least LGB stuck to the brass extrusion at Code 332 imperial.

As regards the pointwork an R1 point LGB wise is 600 centre of radius to centre of rails, it is 300MM long in the striaght and the curve is the same as a standard R1 curve 30 degrees. Hence it all fits together. There is no R2 point in the system from LGB, USA Trains Hartland, or Aristocraft as far as I know. The gap is then to an R3 point. An R3 point is 1198MM radius from rad centre to rail centre, is 440MM in the straight BUT!!!! the curve is only 22.5degrees. If planning a track this has to be taken into account, plus if you use them as facing points to make a crossover between tracks, they work fine but again the distance between centre to centre of the parallel will differ from the R1s and the centre to centre distance of set track curves. I can just squeeze a 7/8ths 150mm wide railcar past a 150MM wide steam loco without my heart stopping LOL! Of course you could add a piece of track between them but that does add to length which may be in short supply and widens the spacings.

Also it should be remembered that only half the frog actually moves in the larger point, the VEE is moulded and it is static. I am trying to remember the name of this type of point it begins with "F" and is something like "Fotheringay". This leads to a largish gap at the crossing point because of the wheel standards used in general by G-scale hence my own problems.

Then came radius 5 curves and pointwork about which I know little and Graeme has detailed the outline dimensions above. All of the key manufacturers seem to have followed closely. Piko is a late comer to the table as far as I am concerned and I know nothing about their system.

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Re: Point radius?

Post by FWLR » Sat Aug 17, 2019 8:33 am

Point and radius have been a bug bare of mine since I started building layouts in N Gauge and it hasn't improved with 16mm..... :lol:

Since generally most people use Peco track, I know there are others. I have just been on Peco's website and this is what their information is on their points..

Medium...

https://peco-uk.com/collections/sm-32-3 ... 4231325730

Small...

https://peco-uk.com/collections/sm-32-3 ... 4231325730

Has they only provide information on R1 and R2 curves, this is all you will find on the site.

R1...

https://peco-uk.com/collections/sm-32-3 ... 5690868770

R2...

https://peco-uk.com/collections/sm-32-3 ... 4231325730

This is of course ready made track, I wouldn't have the foggiest on where to get and buy other radius points and curves. There is of course Flexitrack, but that's a different art in its self. It is for me anyway.... :lol: :lol: :lol:
Rod

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Re: Point radius?

Post by FWLR » Sat Aug 17, 2019 8:47 am

Sorry, I didn't do 45mm. So here are the links.

Small radius point....Their description is not correct, but you will soon realise that it's the smaller radius....

https://peco-uk.com/products/turnout-me ... 4231325730

This is the Medium...

https://peco-uk.com/products/turnout-me ... 5750932514

They only do one curve.... :scratch:

https://peco-uk.com/products/standard-c ... 5745361954

One thing though and it's has I thought, there is a vast difference in price for 45mm, compared to 32mm. I also know it's on Peco's own website, but I assume there is a difference where ever you buy from.
Rod

Life is so easy when I run my trains. :thumbright:

🚂🚃🚃🚃🚃🚃🚃🚃🚃🚃

https://gardenrails.org/forum/viewtopic ... 41&t=11364

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