Large Scale Central

Track switches and curvature degrees.

Track and Trestles
#1

I am looking to start putting in some turnouts and was looking at making some #5 turnouts as I have full size drawings for them. I noticed that when I layed them out they are just slightly longer and have less of a curve in the transistion between track than using two 22.5 degree turnouts which I think has the same radius as a 4 foot radius (or 8 foot diameter curve track). If this is correct would a 22.5 degree turnout be a #5 or is it a #4 turnout. I think that a #6 turnout are 19 degrees and are far too long for my space requirements and as I understand are used with 10 foot radius curves.

Can anyone shed some light on this. I had thought about using a couple of the 22.5 degree turnout to make the crossover, but not sure my 1:20.3 2-8-0 consolidations will have problems going through them.

Dan S.

Photos in discussions
#2

Dan, the first thing that you have to do when using numbered turnouts like #4, #5, #6, and so on is to forget about the degree of radius, because there is no radius in a numbered turnout. Radii exist only in toy turnouts. In a real turnout, or in its model, once the rails leave the frog, they leave in a tangent (straight line), in almost all cases. There are exceptions, but for this discussion, let’s forget about them, they are rare, anyway.

Go with the numbered turnouts, they are less prone to derailments (fewer s curves).

I know this sounds discordant, but this is reality. Next question, do you understand what the numbers of the numbered switches mean?

#3

Yes, in real turnouts the frog is straight, and so is the stock rail across from the frog.

#4

Steve: Yes, the Number of the frog, is the measurement that is use to specifiy the angle of the exiting rails as measured in ratios of 4 to 1, 5 to 1 and 6 to 1 and so on, where the 5 would be in modeling terms 5 inches down the rails where the rails would be 1 inch apart. Not exacty said in the best terms, but yes I do know how they are numbered.

I had laid two 4 foot radius cuvres in an S curve just to see where I wanted to put the cross overs and I do agree that that gave me pause as to weather my 2-8-0’s would go through them without any problems, even though they should be able to negoiate a 22.5 degree turnout.

So I will go ahead and hand lay my own #5 turnouts.

Dan S.

#5

I for one am lost. As long as I have been in model RR this still puts my brain in a fog. Even after being shown pictures. One of these days Steve your going to have to use your fingers and point. I think the only way I will ever understand this is to be shown. This is one area where I just am dense. It doesn’t sink in.

#6

Dan, you will be a lot happier with two #5 turnouts as your crossing, than trying to use two four foot radius turnouts. The s curves would be akin to using two four ft curves laid end to end, without a straight in between, a sure invitation to derailment.

I measured the frog on a five ft radius turnout from Aristo, it measured 3.5, so the four ft radius frog would be even wider. That doesn’t mean that a five ft radius (10 ft diameter) turnout is a #3.5 turnout, only that it has a #3.5 frog.

BTW, a “crossover” occurs when two tracks intersect and cross each other, but at different elevations, one over the other. A “crossing” occurs when two tracks intersect and cross each other, on the same plane. A fine point, to be sure, but…

#7

2 #6 turnouts

The rails run straight through the frog.

#8

Devon Sinsley said:

I for one am lost. As long as I have been in model RR this still puts my brain in a fog. Even after being shown pictures. One of these days Steve your going to have to use your fingers and point. I think the only way I will ever understand this is to be shown. This is one area where I just am dense. It doesn’t sink in.

Sectional track is comprised of curves and tangents (straights) Switches MUST have a curved section to mate with other sectional TOY train track.

Numbered Switches;

Prototypical switches are an angle of deflection (points) and straight track,from point butts through the frog and beyond. That’s the standard, special switches are variants according to need, ie; curves and restricted space.

See below; only the lead in track bends making the Angle of Deflection, the tracks run straight beyond…

The number of the switch can be measured from the frog and beyond. A number 6 would be 1’ apart at 6’ out.

Also notice the Harp Switch stand; this used to be a 3 way switch.

Foreshortening makes the angles look more abrupt than they roll.

Trains are Fun.

John

#9

John Caughey said:

The number of the switch can be measured from the frog and beyond. A number 6 would be 1’ apart at 6’ out.

Also notice the Harp Switch stand; this used to be a 3 way switch.

Foreshortening makes the angles look more abrupt than they roll.

Trains are Fun.

John

Ok this is where I am dense. I might want make sure I understand one thing right off the “frog” is the thingamajig where the to rails intersect with one another right? The two outside rails never intersect another rail but the two inside rails (after they separate) cross each other. This intersection piece is the frog right?

If so, so when we say that a #6 switch is 1’ apart at 6’ what are we describing as being “apart”? If I am understanding this correctly as the two inside rails leave the frog in their respective directions they increasingly get farther apart since both leave as a tangent. so are we saying that if the two inside rails are separated by one foot, six feet away from the frog then that is a #6? Basically what we are doing is describing the rate at which the tracks diverge past the frog? The lower the number the faster they diverge and the bigger the number the slower they diverge? I assume then if I am correct in this that as the number increases then so must the length of the frog and the overall switch itself. And conversely the lower the number the sharper the radius of curve inside the switch itself? I now once they leave they are straight but like you said they must curve at some point and that point is between the ends of the sliding rails and the frog right?

Do I finally have the RR switch figured out? Please tell me I do.

#10

By Jove I think you’ve got it!

Wow way to go!

Right on!

Happy Rails!

John

#11

On some Special switches everything can bend, but for now you are on the right track… oh groan.

The frog is the Doohicky that allows the flanges to cross the other rail. Sorry if too tecknickle.

John

#12

Now that I am finally wrapping my brain around this it is a good time to insert this link here

http://www.largescalecentral.com/forums/topic/23019/turnout-frogs-numbers-and-angles

I think I can keep up with Bob now and it might be useful for others like myself to review this now.

#13

This is good since I plan on building my turnouts to replace my Arsito wide rad switches. I like the switches Ken but what part of the rails actually move. Its hard to tell from the picture. Then the same for the photo John posted. Also why would arsito, LGB Piko etc… all use plastic frogs where they are raised up causing the wheels to jump slightly. Why cant they do what Ken does. To me it seems more realistic and you don’t have to worry about that hop as the cars roll over the frogs.

I need a lesson on building turnouts 101 for dummies.

#14

I posted a Stub Switch where one actually might say It’s time to bend the iron!. The rails are bent to mate to the various routes. You can’t see the fixed point in the pic. There would be spikes on each side of each rail.

Ken’s points are 6-9" from where they touch the other rail to their heels. Then fixed rail beyond. The pic is foreshortened by the lens. Look where the spikes stop on the inner rail. The points other end begins there. The actual points are what touch the other rail. The whole section of rail gets the name.

Hope that helps. I have seen longer high speed switches where the points are one long rail to the frog, but the length allows for easy flexing (bending).

Build from a plan, the locations will be easier to understand when looking from over head.

John

#15

If all wheels were the same you wouldn’t see a hop.

The reason it’s done is to prevent wheel drop caused derailments. The idea is to have the wheels run on their flanges where the rail gaps are. Our model wheels and track are crude compared to 1:1. Tight turns, like R1, wide gaps, scale wheels vs semi scale…too many variations often derail without the raised flange way.

Now flange running is becoming prototypical! Life imitates Art!

John

#16

OK, Devon, now comes the fun stuff, rolling your own.

Here is a pic of a home built turnout from Crispin B. Hollinsheads website “One way to Build a Switch.” Crispin describes himself as an Optimistic Catastrophist, so he would probably fit in well here.

You asked what part of the turnout moved. It is the pointy track that is attached to the ground throw, which is on the two longish ties on the right end of the turnout above. Serendipitously, those pointy pieces of track are called “points,” for some unknown reason. On full sized turnouts, and some better model turnouts, the entire rail, from the point to the frog will move as the “switch” is thrown. On toy turnouts, only about half of the point rail will move, making it easier to use flimsy materials. Note that both diverging routes leave the frog as tangents.

For more than you want to know, at this point, go to Building a Switch, on Crispin’s site.

#17

Steve Featherkile said:

You asked what part of the turnout moved. I did? I wouldn’t put it past me but that is about the only thing I knew about switch operation.

For more than you want to know, at this point, go to Building a Switch, on Crispin’s site.

Thanks for this i will check it out?

#18

Sorry, Devon, it was Shawn that axed what part of the rails actually moved, and I suppose that he was talking about Ken’s stub switches, where … I’ll let Ken explain those things. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

#19

Steve (and others),

Well as I am pursing the site you mentioned this moves the direction of conversation to the theoretical in how does one determine what they need or can handle. So I know what a #5 switch is now but how do I determine what switch I need. On that sight he states he wants to maintain 8’ radius curves and that a #5 equates to that. How so? If I determine I want 4’ min radius curves on my railroad then what frog number gives me that angle. It would seem to me that this would only be an issue in trying o build a switch on a curve. If the switch is on two adjacent straight tracks wouldn’t the limiting factor be how long the switch can be. I would assume that one would want the longest frog they could get there by not having such a sharp divergence and derailment problem; a smoother transition if you will.

On my RR plan I wont have very many switches at least to start. I am planning 8; three on a Wye, one siding, and a double crossing (x shaped thing to switch from one loop to the other and back again like Kens above only with a mirror of it doing the opposite making a cross in the middle. The easiest will be the siding as it is a split off a long straight stretch. On the Wye one leaving the main will be on a straight stretch where the spur continues straight and the main begins an 8’ dia curve. The other will be in the middle of said curve with the spur heading straight but the main being in the curve. the converging tracks will be a wye. Then is the “thing” where the two loops meet at grade and are joined so that trains can remain on the loop they are on or switch to the other loop and vis versa.

now I don’t expect an exact asnwer to my situation but when the time comes to build these what determines how these switches will be built, what number, length of frog ect.

BTW sorry for hijacking the thread but it seems to be a relevant question to the topic

#20

Devon, the only thing I can say is to reiterate what I said earlier. You can’t equate a radius with a numbered turnout. I’ll stop here, because I have a headache and I’m not making any sense.