Turnouts explained please


gator do 65

gator do 65

Member
Ok guys and gals I need some explanation on turnout terminology?

Such as;
Frogs powered or non powered, #4,6... turnouts, snap turnout, tortious machine, and of coarse my mind is drawing a blank now! I know there is more! so if you can think of other strange named items that pertain to turnouts please throw them out there in hopes it'll help!

Thanks in advance, Gator
 
Briefly, the number of the turnout corresponds to the sharpness of the curve in it. The higher the number, the broader the curve. A powered frog, as its name implies, has the center "vee" part supplied with power. Insulated, that part does not have power. Power routing turnouts direct current toward the section facing the track in the direction the switch is thrown.
 
The best way to determine if a frog is powered or not is to use an ohm meter with one lead on the frog and the other on one of the closure rail. If there is continuity then the frog is powered. If no continuity, it is insulated. Plastic frogs will be insulated, but sometimes it is difficult to tell. Some metal frogs are also insulated because of gaps cut on both sides of the frog. Metal frogs that are insulated may be selectively (to match the polarity of the adjacent closure rails) by running wires to a DPDT relay, toggle switch, or contacts on a switch machine. In some instances a "live" frog will take the polarity of the closure rails, which take their power from the stock rails. Good continuity between the switch points and the stock rails will determine which route is powered. This is okay as long as continuity is good. Dirt or oxidation can cause problems with this type of turnout.

Technically, a "turnout" is the whole assembly, including the frog, stock (outside) rails, closure rails (that lead to the frog), and the moveable switch points that change the direction of the train depending how they are thrown. A switch machine throws the switch points on the turnout.

A "snap" turnout is generally one of Atlas' ready-to-install with a manual or twin coil switch machine. Atlas Snap turnouts have the diverging route curved for an 18-inch radius. Their Custom line has the diverging route straighter beyond the frog, even though they ostensibly have the same number, #4. In actuality the Custom Line #4 is about a #5 or so.

Hope this helps.
 
The size of a switch is not necessarily the curvature, it's the rate of divergence of the frog. A #4 frog the two rails will diverge one unit for every 4 units of distance. A #6 frog will diverge one unit for every 6 units of distance. If you measure a #6 switch the frog rails will be about 1/4" apart 1 1/2" from the point of the frog.

On a real switch the route through the frog is straight, not curved. On most model switches the routes past the frog are straight, not curved so there is no continuous curve through the switch. The exceptions are some of the Atlas Snap switches and Peco small turnouts.

You can also wade into a big argument about "turnout" versus "switch". Mostly semantics.

Powered frogs are metal and have track current in them when the switch is lined, they require some sort of switch or contacts to route the power.
 
My take on a turnout is that there are 2 parts to the turnout, the front part is a switch and the frog is a wye.

Together in America we refer to them as turnouts.
 
gator do 65 said:
...
, tortious machine, and of coarse my mind is drawing a blank now!
Click to expand...

I believe you are referring to TORTOISE machines - Tortoise is a brand name of electronic switching devices for turnouts. I think they are only usable on DCC tracks. They receive input from the throttle based on a specific ID code for each Tortoise and either "open" or "close" the switch. I used eight of them (four each) on my two double-crossovers.

Additionally, something that I am experimenting with on my new build is a FROG JUICER. I received a Hex Frog Juicer (HFJ) in the mail today and will install it tomorrow. Essentially, you hook up the four 'frogs' on the double-crossover to the HFJ and it will automatically reverse the polarity of the frog when it senses a short across the rails.
 
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GDSmith said:
I believe you are referring to TORTOISE machines - Tortoise is a brand name of electronic switching devices for turnouts. I think they are only usable on DCC tracks. They receive input from the throttle based on a specific ID code for each Tortoise and either "open" or "close" the switch. I used eight of them (four each) on my two double-crossovers.
Click to expand...

Tortoise machines do not require DCC. They can be activated using a DPDT toggle switch with the correct wiring. The way they're actuated is by differing polarities. The DPDT toggle switch can be wired so that each position supplies the opposite polarity and the switch can then be used "manually" this way.
 
FWIW. Tortoise switch machines are called that because of their slow movement. They have been around much longer than DCC.

Steve
 
gator do 65 said:
Ok guys and gals I need some explanation on turnout terminology?

Such as;
Frogs powered or non powered, #4,6... turnouts, snap turnout, tortious machine, and of coarse my mind is drawing a blank now! I know there is more! so if you can think of other strange named items that pertain to turnouts please throw them out there in hopes it'll help!

Thanks in advance, Gator
Click to expand...

Snap turnouts are basically Atlas turnouts that are actuated by a solenoid that's pre-mounted to the turnout. They are the simplest to install and wire, but have a bulky switch machine that is in plain sight and looks ugly. They also "snap" the points instantly, which is of course far from prototypical. Tortoise machines are mounted under the layout and out of sight. They use a wire that goes through a hole underneath the switch and is then inserted into the throwbar of the turnout in order to position it. Thus they give the best look to your layout, but you do have to drill a hole for the wire, mount the machine, wire it etc. If wiring it for a non-DCC application, it does require a specific type of toggle switch wired a certain way to perform correctly. Tortoise machines move the points slower and more silently, and for that reason too are more aesthetically pleasing than the snap switches.

People have explained the #4 etc., so I won't go into that.

Powered frogs (electrofrog) mean that the point where the rails diverge in the wye of the turnout is actually powered. This allows more reliable slow-speed operation, especially of steam or small diesel locomotives. Powered frogs do have to be isolated with insulated rail joiners on the inner two rails, and may require special wiring to work correctly. Some newer turnouts are DCC-friendly if you are planning to use DCC, and you should look for those specifically if so. Older powered-frog turnouts that are not DCC-friendly will require you to cut and gap the frog in order for it to function properly. Insulated frogs (insulfrog) may cause some locomotives to stall if going through the turnout at very low speed, though how much an issue that is will depend on the brand. I use N-scale insulfrogs made by Peco and have had no issue with locomotive stalling. Other scales, brands, etc. are obviously different. The advantage to the insulfrog is that it does not require any special wiring, rail gapping or insulated connections. Just hook it up and it works.

Hope that helps and didn't just muddy things up :)
 
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GDSmith said:
I believe you are referring to TORTOISE machines - Tortoise is a brand name of electronic switching devices for turnouts. I think they are only usable on DCC tracks.

Additionally, something that I am experimenting with on my new build is a FROG JUICER.
Click to expand...

If your switch machines are DCC enabled I would guess that you have Circuitron "Smails" - which are basically Tortoise devices with a built-in DCC decoder.

Tam Valley Frog Juicers are a good choice if you don't have any spare contacts on your switch machines to switch power to the frogs OR you simply don't quite understand how to wire such a set of contacts up.

The Frog Juicer is pretty near a foolproof solution to powering a frog. It is particularly good for complicated things like double crossovers where the wiring can get quite tricky.
 
Here are a couple of diagrams that might be helpful.

First is a generic model railroad turnout with the various parts identified.

turnout_nomenclature.gif


Note that the frog can be either metal or plastic, depending on the design of the turnout. If the frog is metal, it will be electrically insulated from other parts of the turnout. Modelers can choose whether or not they wish to power the metal frog. If it is not powered -- or if the frog is plastic -- there is a chance that a locomotive might stall when passing over the frog because it receives no power from an unpowered frog.

To illustrate turnout numbering, here are scale drawings of Atlas Code 55 N-scale Turnouts.

Atlas_Code_55_Turnout_Diagram.gif


Note that the overall length of the #5 and #7 turnouts is about the same. However, if you look closely you will see that the geometry of the two turnouts is subtly different.

- Jeff
 
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