How do I calculate this?

Model Railroader General Discussion (Model Railroader)
1

I want to know the distance between the 2 tracks (red arrow). Is there a way to calculate it? The turnouts are Walthers/Shinohara #4.

2

I would just do it the easy way! Run a straight section of track up from the bottom diverging rail long enough to get close to the upper one and just measure it with a ruler. Just make sure it is straight so you get accurate measurements.
terry

3

Thanks for your answer. Yes I know what you mean but I’m trying to aviod to measure it with a ruler. I really want to calculate it. Maybe someone with trackplanining software can help me out here?

4

The actual spacing between tracks is going to depend on the distance between the turnout points and the true angle of the frog… For a close guesstimate, figure 2.25 inches (57.15mm) on #4. If it’s off and you need it to be exact when you lay it out for real, you can trim the turnouts to make it work.

Jeff
[swg]

5

Sorry, I thought it was too easy. I try to stay away from math as much as possible so I always look for alternate methods.
Terry

6

It aint you, it’s him. He’s tryin to complicate it all up as usual, but actually, in the end, he will have the more accurate answer.

7

There are several ways to do this using some basic Trig functions.
The easiest is to use the Pythagorean theorum. Since we are finding the side B in a right triangle we will need the measurements between the two points on the A side as well as the C side. These can both be measured and use the formula to find B. Since you will be using a square to find the length of the A side anyway you could measure distance from the square to the point and determine this.Anyway you do this you will need to assemble the two turnouts together to get at least 1 measurement, that being the one between the two points.

Dan Pikulski
www.DansResinCasting.com

8

I am completely unqualified to answer this but many years ago I wasted a lot of time in math classes. A #4 turnout goes 1 unit east for every 4 units north. Your measurement could be as simple as A/4 where A is the distance from the point of the first turnout to the point of the second turnout. Remember this is center to center or outer rail to outer rail or inner rail to inner rail, not the distance between the tracks. For that subtract the width of the track.

Fire away if I am totally off base.

9

Sweden: you have a problem.
My 2004 Walthers’ Catalogue lists the length of the turnouts as 8-15/16" or 22.3 cm but not the frog angle on this size turnout only. The frog angle is crucial. Bukwrm’s formula would work if you wanted a very loose approximation. A turnout can have an equivalent frog number of anywhere between 3.5 to 4.44 and still be designated a #4 turnout. This is why you cannot swap brands if you have to replace a turnout without having to make other adjustments to the approaching trackwork. A number 4 Walther’s will have a slightly different angle than Peco’s short raidius, or an Atlas.
Just for reference, Bukwrm’ formula would give you approximatel the 2.25" recommended by rolleiman.

10

2.25" (57.15mm) is good for me.

When I measure it (very fast) I got an answer around 60mm.

Thanks

11

As usual??? No no no… I just want to lay my track in a good way. [:D]

12

I wouldn’t try to calculate it – just put the two turnouts together with a piece of straight track connected to the rear one, and measure the distance. If the turnouts are anywhere close to NMRA standards, there should be approximately 2 inches (5cm) center-to-center between the tracks.

13

Just slap two straight tracks onto those switches and eyeball the distance.

If yer happy! Great! If not add track between the switches until you get the spacing you want.

And yes a ruler is helpful.