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HI,

I'm new at this model train stuff but I am learning a lot by just plugging ahead. I have a small setup, HO scale on a 4x8 sheet. I have 2 loops with 2 crossover from one to the other loop. I'm looking to buy a couple of lefthanded turnouts, code 100 and I'm seeing something called #3, or #4, or #5. What does the #3,4,5 mean?
 

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In America, the frog angle is specified by the frog number, which is the ratio of the length to the width.

In HO model railroading, a #4 is used for yards and sidings in some cases. On mainlines, #6 is usually the minimum used, and #8 or #10 is better if you have the space. On a small railroad such as yours, #6 is fine for crossovers without sacrificing a lot of real estate. It is what I used on smaller layouts, and still do even though my current layout is much larger now.

#4 turnouts are seldom used for high-speed mainlines as the angle is too severe to negotiate at speed. #6 is OK, but #8 would be better for high speed crossings.

Speed of course is relative. What is fast to you may no be fast to me and vise-versa. I like to run at a scale speed of between 30 and 50 MPH best as I can judge. There is a speed calculator available that I use occasionally to see if I'm close to what I think my trains are running.

https://mysite.du.edu/~jcalvert/railway/turnout.htm

Speed calculator:

http://www.stonysmith.com/railroad/speedcalc.asp
 

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The number is suppose to be the amount of run on the straight through rails compared to the divergence on the diverting rails. So a #4 should be four units of straight through and one unit of divergence, 4" from the frog on the straight through section should give you 1" of displacement on the diverging rails. The higher the number, the less amount of divergence in a given distance. Curved turnouts tend to give the radius of the two curved routes. Wye turnouts is the divergence between the two routes, so a common wye is a #3, which sounds sharp, but in reality is comparable to a #6 turnout, the wye has two diverging routes. Gauntlets would be oddball and probably hand made anyway.
 

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Welcome aboard!

HI,

I'm new at this model train stuff but I am learning a lot by just plugging ahead. I have a small setup, HO scale on a 4x8 sheet. I have 2 loops with 2 crossover from one to the other loop. I'm looking to buy a couple of lefthanded turnouts, code 100 and I'm seeing something called #3, or #4, or #5. What does the #3,4,5 mean?
knight80;

Welcome to the forum! To answer your question, those numbers you saw are called "frog numbers" and they indicate how sharply the two possible routes through the turnout split from each other. Since you're looking for left-hand turnouts, I'll use them as an example. The frog number is simply the number of units a wheel must travel forward to get one unit of sideways travel away from the main route, and toward the "diverging" route. (often onto a siding)

For instance, if the wheel had to travel 5 mm. forward to make one mm. of progress to the left (on a left -hand turnout) then that would be a #5 turnout. If the wheel had to roll 8 mm forward to get the same 1 mm of leftward progress, then that would be a #8 turnout. On a practical level, the higher the frog# is the less sharply the diverging route splits away from the main route. A #5 turnout is adequate for most model railroad uses. Some situations, like the crossovers you mentioned, call for higher frog# turnouts to minimize the sideways swing from left to right as the train passes through. I like to use at least #6 turnouts for crossovers and will use #8 turnouts wherever I can fit them. The bigger frog # turnouts are longer than the smaller ones, and thus they need plenty of straight track length to fit into.

May I ask what type of turnouts you are using now? If they are Atlas brand, and did not have a frog # on the package, then they are probably Atlas "Snap Track" turnouts. These have a different shape than the Atlas "Custom Line" turnouts, and all other commercial model turnouts.
The "Snap Switch" turnouts have one 9"straight route, and one curved route that is similar to an 18" radius curved section of Atlas's "Snap Track." This is so the snap switch turnout can take the place of either an 18" radius curved section or a 9" straight section of Atlas snap track.

If you have the snap track turnouts, do they work well for you, or do you have problems with derailments on these turnouts? While the snap switch turnouts are what most new modelers start out wit, and many stick with, many other modelers have upgraded to better brands. (Peco, Micro Engineering, Walthers/Shinohara)

The files below are some that I wrote to help new modelers, like yourself. The first two of them are specifically about turnouts, and the rest are filled with general information about model railroading. I hope you will find them useful.

Again, welcome;

Traction Fan:smilie_daumenpos:

View attachment All AboutTurnouts revised.pdf

View attachment Improving Atlas turnouts pdf version.pdf

View attachment WHERE DO I START 3.pdf

View attachment 1 How to build a better first layout.pdf

View attachment 2 How to build a better first layout.pdf

View attachment 3 & 4 How to build a better first layout.pdf

View attachment 5 How to build a better first layout.pdf

View attachment 6 How to build a better first layout.pdf

View attachment Model Railroad Terminology 2.2.pdf

View attachment MODEL RAILROADING ON A BUDGET.pdf
 

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Ks80,
At the end of the frog where the main and diverging routes are (frog: the channeled portion where the 2 inside rails of the 2 routes crisscross), it's the measurement of rail length from the frog outward..IE. If there is 1 foot between the two inside rails diverging past the frog at 4 ft in length, It's a #4 switch. If The there is 1 foot between them at 6 feet out from frog, it's a #6 switch; 1 foot at 8 feet out is a #8 switch.. each becoming more and more obtuse than the prior..So, a #12 would be ? You tell me..
I believe the 1:1 scale goes up to #22 or #24 for very high speed traffic making a crossover move without needing to slow down. These are thrown by remote from a tower, not by hand...
M, Los Angeles

PS. If not too late, I'd stay away from code 100 (especially if it's the old Atlas black-tie stuff). Code 100 rail scales out to be like 13-14" tall in real, have plastic frogs [cause stall outs] and so looks kinda goofy. No real rail is that tall. I'd suggest you go with code 83 flex and/or sectional track..(Exception: If your engines and cars have the old overly-deep wheel flanges of the 1950s stuff, then yes, go code 100.) if your stuff is all modern made, and with knuckle couplers, go 83.
 
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