Snap Track Radii

[RhB_HJ]

Hi all,

In order not to bury this in the other thread ("Is the trend for new engines that need ever wider diameters a good idea?") here are some of the basics.

1) model railroad curves are generally referred to as having x amount of radius i.e. from the theoretical center point to the center between the two rail (track center) is x.

2) LGB's measurements (until recently) were always given as cm.

3) ARISTO-CRAFT gives the diameter (don't ask me why!)

4) Aristo's and LGB's track are both Code332; which means the height of the rail profile is .332"

Now to the LGB track:

• R1 = 60cm (600mm)
• R2 = 76.5cm (765mm)
• R3 = 117.5cm (1175mm)
• R5 = 232cm (2320mm)

The first three of the above are from the 2000 LGB catalogue, the "R5" is from their website. The mm is to lessen the confusion in most conversion reference lists they have 25.4mm = 1"

If you're looking for a nice converter Metric to Inch or vice versa have a look at this www.stanstrains.com

LGB makes turnouts for R1 (12xxx series), R3 (16xxx series) and R5 (18xxx series). All of the LGB turnouts use a radius on the diverging route, so to calculate the frog number you need a conversion table for the frog-angle.

• R1 = 30º (approx.#1.9)
• R3 = 22.5º (approx. # 2.5)
• R5 = 15º (approx. #3.8)

The approx is because I'm too lazy to fire up CADrail right now.[;)][:)]

Hope that helps!

[Anonymous]

Quote
3) ARISTO-CRAFT gives the diameter (don't ask me why!) (end quote)

Cause they can!

Nice piece of Math work Hans, on the frog angles. Close enough.
Grant

[Anonymous]

I love it when you talk dirty; but really i appreciate all those calculations and I must say I have a different idea to what the authorities heve here about metrics.

Many people do not agree with the idea on centimetres at all. The engineering standard in many areas is to go in jumps of 1000 and i support that. micro, milli, unit, kilo and mega.

My new section i am working on has all the radii at 1.1 M not 101 centmetres or 1100 mm.

When you are doing what we are doing now removing 2 M high palm trees, these calculations are really not of a lot of interest to us but I'm sure that will change when I start laying down track because all my points will be LGB R3 I think I will need 5 of them 3 lefthanders and 2 righthanders.

Rgs


Ian Kawna

[vsmith]

For all those non-metric savy types like me, heres the conversion into english:

R1 = 4' dia
R2 = 6' dia
R3 = 8' dia
R5 = 10' dia

Aristo sells:

4' dia
5' dia
6 1/2' dia
8' dia
10' dia
12' dia
20' dia

I might be missing a few but this is whats out there. Yeah, I know, the metric conversion is ballpark, not scientific.

[Anonymous]

Thank you Sir!!! My fingers not tired with all those cals....[:D]