There are two basic types of turnouts; Power Routing (a.k.a. all live and live Frog), and Non-Power Routing (a.k.a. insulated Frog and non-live Frog). Peco makes both types under the names of ElectroFrog and InsulFrog, respectively. Specific information about both of these is on their respective pages. This page is dedicated to turnout terminology and information in general that applies to both types.

First, we'll identify all the turnout parts:

The Throw Bar is also known as the switch rod by some, and bridle bar by others. But since most people in the modeling world call them throw bars, that's what we'll stick with.

The Frog is probably the most important part (at least for the discusses we'll have here and on other pages). The Frog is what makes the difference between Peco's ElectroFrog and InsulFrog turnouts. It's also how most American turnout manufacturers designate how much of an angle the divergent route takes.

The Frog number is based upon the angle at which the Divergent Frog Rail leaves the Frog, in relation to the Through Frog Rail. The Frog number can be calculated by measuring a distance from the Frog down one of the Frog rails, and dividing that by the distance between the two Frog rails at that point. For example, if you measure 2 inches down the Through Frog Rail from the tip of the Frog's point, and 1/2 inche from the outside of the two Frog rails at that point, you will have a #4 turnout (2 ÷ 0.5 = 4).

If measuring from the tip of the Frog, you must measure across the rail-heads, as shown here. This is how we did it to calculate Peco Frog numbers.

If measuring from the "V" created by the Frog rails coming together, then you also measure between the rail-heads of the Frog rails.

If you measure from the intersecting point of imaginary lines down the middle of the rail-heads, then you would measure between the centers of the two rail-heads.

This doesn't mean you should measure two inches down on every turnout and make your calculation there. You should measure the length of the Frog rails, and the distance between them at the end of the Frog rails. Doing this you'll come up with figures such as: 1.86"÷ 0.34" = #5.47 turnout (this is actual measurements from an Atlas #6 turnout). It's very difficult to measure these things accurately with a ruler, so we use a set of calipers that measures in millimeters. Using millimeters makes the previous calculation look like this; 47.3 ÷ 8.65 = 5.468.

You can also calculate what a turnout number is from the Frog angle (that is, if the turnout is made with the Frog rails following the Frog angle for a long enough distance to measure it). For example, a 10° angle works out to be a #6 Frog. The problem is that the Frog rails don't follow the Frog angle on most turnouts, and many turnouts have curved rail coming right off the Frog. For example, Peco's small, medium, and large radius turnouts all use a 10° angle Frog (about 1/3-inch long). The difference is made up in the Frog rails that curve away from the Frog. Therefore, you can't gauge these turnouts by the Frog angle. As you've seen above, the Atlas #6 turnout may have a Frog angle of 10° (I'm not sure), but because the way the turnout itself is made, the outcome is a #5.5 turnout

Peco realizes this, so they don't gauge their turnouts by the Frog number. Instead, they provide other valuable information to help size up a turnout for your need (including the length of the through route, and radius of the divergent route). You'll see in our listings of these turnouts that we've included the length of the divergent route, a comparison to Atlas turnouts (for HO scale) for those who are use to Atlas Frog numbering, and the actual measurement/calculation to determine the turnout #.

Note: While it's the Frog that is numbered, I use the term "turnout #" because the Frog rails deviate from the actual Frog number to make a turnout configuration different than the Frog indicates.

One thing you'll find with Peco turnouts is that the divergent route is smooth. If you take a close look at an Atlas turnout, for example, you'll see that there's a bit of a kink (a place where the rail takes a sharper bend) just beyond the Frog. Peco turnouts are smoother around the divergent route. This is extremely valuable when switching a siding off of a curve. In this situation, the normal divergent route becomes the mainline (closed route), and the straight through route becomes the thrown route. By choosing a Peco turnout that matches the radius of your curve, you won't have a kink in the mainline at that point.

Lastly, it doesn't matter whether you're modeling in N, HO, G, or any other scale. A #4 turnout has the same angle and diversion in all scales. But a #4 turnout provides a medium radius turnout for HO scale, and a large radius turnout for N scale (even though it's the exact same radius).

Peco Point Spring:

Peco turnouts use a spring to hold the points tight against the stock rail. Some people remove these springs to make them easier to operate. For example, Tortoise machines have a hard time overcoming the spring tension to move the points to the other side. But, this spring tension is important, especially for DCC. It provides more positive power connection to the points by keeping the points from vibrating when the loco is traversing them. And even though the Tortoise machine holds pressure on the points, it's not as much as the spring does (evidenced by the fact that the Tortoise is not strong enough to overcome the spring tension). Instead of removing the spring, simply adjust it so it's not quite so strong. This allows the Tortoise to overcome the spring, and allows the spring to supplement the pressure the Tortoise provides.

Spring adjustment can be made in two ways. If you look closely at the spring housing, you'll see two metal tabs that hold it in place. If you bend these tabs up, that spring housing will come up to expose the spring. At that point you could spring the spring a little to weaken it's tension, and replace it. But if you look at the bottom of the spring cover, you'll see notches. At first glance, one might think this is a way to adjust the spring. Unfortunately, these notches are too large to do fine adjustments. But, knowing how this works will allow you to make minor adjustments with this. Simply place a small blade screwdriver between the housing and throw bar and tweak it backward just a little - (it moves pretty easily, and it doesn't take much (you don't even have to loosen the metal tabs).

Another point about the spring is that it doesn't always provide the same amount of tension in both directions. The only time you'll ever notice this is if using a turnout motor that is just barely powerful enough to overcome the spring tension in the weakest direction. In this case, the motor will not be powerful enough to overcome the spring tension in the other direction. The solution is to either weaken the spring or adjust it a little looser, or use more voltage or a more powerful motor.

Set Track:

This is a clever track system whereby you can design a wide variety of track plans with track pieces that fit together without having to bend or cut special pieces to make everything work. That is, you can buy short curved pieces where a certain number of them will make a perfect circle. Set Track turnouts are designed to fit right into these schemes by having specific lengths just like the short curved and straight set track pieces.

Set Track pieces are designed for people who don't have a place to set up a permanent layout, so they can quickly put a track plan together, run on it, then take it apart again. Using Streamline (non-Set Track) turnouts in a Set Track plan will require cutting and bending of custom pieces to make them fit. However, Set Track pieces can easily be used in conjunction with Streamline turnouts when designing and building a permanent layout (because you'll be using flex track and making lots of custom fit parts anyway).

Note: We carry the Set Track turnouts and crossings, but do not carry the Set Track curves and straight pieces.

Code Track:

Comes in different heights (expressed by a code size). One code point is equivalent to 1/1000 of an inch. Therefore, Code 100 is 100/1000 of an inch, or 1/10 of an inch high. Peco's HO-scale track comes in Code 100, Code 83, and Code 75. Their N-scale track comes in Code 80 and Code 55. They call their HO-scale Code 75 and N-Scale Code 55 "Fine Scale". Peco's N-scale part numbers note this with a suffix "F". We use the "F" in Loy's Order numbers for all Fine Scale track, including HO.

Quality makes the difference:

Peco turnouts are built with the highest precision of any turnouts we've looked at. You can tell it the instant you just hold one in your hand, and move the points back and forth. Parts fit like they are supposed to, operate precisely and firmly, and the turnouts lie flat and solid on the roadbed like they should. All in all, you'll be very happy with Peco turnouts.

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Last modified:  December 29, 2008