Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Peco Turnouts

2235 views
4 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    May 2009
  • 11 posts
Peco Turnouts
Posted by 2 by 4 on Friday, December 18, 2009 5:10 AM

What is the difference between insulfrog and electrofrog turnouts.

Do you have to do somethnig different on the layout using DCC for each?

  • Member since
    February 2005
  • From: Southwest US
  • 12,914 posts
Posted by tomikawaTT on Friday, December 18, 2009 9:56 AM

Briefly:

  • Insul(ated) frog - the points and closure rails, and the rails beyond the frog, are wired so a locomotive can take either route regardless of point position.  They won't have wheel-back shorts at the points, but sometimes have problems at the frog with wider-than-standard wheels.  No special rail gaps are needed and they can be powered from either end.
  • Electrofrog - the points, solid frog and closure rails are a single electrical unit which must be powered, either through the closed point or through contacts on the switch actuator.  Wheel-back shorts between the open point and adjacent stock rail are possible (metal wheels, substandard back-to-back clearance) and entering the turnout from the frog end with the points thrown against the movement WILL cause a short - every time.  Frogs must be isolated by insulating rail gaps, preferably before the clearance point(s) of the diverging tracks.  Electrofrog turnouts may be powered from the stock rails, but NEVER through the rails leading to the frog.

Electrofrog turnouts require more attention during tracklaying and are very unforgiving of improper or careless train operation in both DCC and analog DC.  They do offer more solid rail contact to units with short pickup wheelbases.

Insulfrog turnouts are simpler electrically, but may cause problems for units with short pickups or wide, flat wheels.  Since I run locomotives with blind drivers, and MU cars with short pickup wheelbases, the Peco insulfrog that I tested was a non-starter.

Chuck (Modeling Central Japan in September, 1964 - on flex track with hand-laid specialwork)

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Friday, December 18, 2009 1:04 PM

Not much to add except the following:

a.  I use the insulfrog #6 Code 83 Customline (meaning they are the N. American style that have straight paths at the frog and beyond...) and am happy with them;

b.  If you have wide and/or out of gauge tires, you could bridge the two close-set rails on the far, diverging, side of the frog...but after the insulating black spacer put there to isolate the frog.  By that I mean the frog will be isolated, and you will successfully negotiate that part (assuming the gauge problem isn't so gross as to snag flanges on the guards around the frog...), but the problem comes when that wide metal tire passes just beyong the black plastic spacer and makes contact with the powered rail again on either route.  It just happens that the outer rim also contacts the adjacent rail, even if for a fraction of a second, and your engine will come to a sudden halt when your system immediately cuts power.  You can negate this by having trains move through the turnouts quickly...momentum will do that for you, but would you be likely to have a successful negotiation of a turnout with wide or narrow wheel gauge?  Maybe, but not always, and certainly not at speed.  If the tires being wide is the principle cause, then speed will be irrelevant.

The fix is to paint the first 1/4" of the two diverging rails's surfaces with a barrier of some kind.  Often people use urethane, varathane...something like clear nail polish.  This is durable, but it doesn't last that long and must eventually be re-done.  Let it harden for at least an hour before you run trains across such a painted surface.

c.  a more permanent fix is to carefully chose the right place and saw through one of the two rails just past the black spacer.  You would want at least two ties holding the segment you isolate by doing this, or you'll get a floppy piece of rail...not good.  Problem is, although this is a good and permanent fix, it also effectively lengthens the frog...the dead frog...and you may find that now one or more engines can't negotiate the turnout without stalling and needing a nudge with the Mighty Hand.  In my case, my smallest wheelbased engine is the tiny Proto 2000 SW8.  With the traction tire axle set that the factory installed, it was a nightmare.  When I swapped that axle out for metal tires, my problems went away.

-Crandell

  • Member since
    January 2005
  • 550 posts
Posted by hdtvnut on Friday, December 18, 2009 5:23 PM

Chuck, if the electrofrog is a code 83 or code 75 Peco (but NOT a code 100, an older design), it is quite easy to not only lessen, but completely eliminate the possibility of a wheelback short at the points, the frog, or anywhere between.  The problem is that Peco only half describes how to do the modification. 

Assuming you plan to power the frog externally by contacts on a Tortoise or otherwise, the procedure is 1. cut both bottom-side jumpers connecting the the front halves of the closure rails to the back halves, and, 2. add jumpers between the front halves and the stock rails.  There are gaps in the bottom plastic for these jumpers, but Peco does not mention them.

The important design improvement Peco made was to move the gaps ahead of the frog away from it to a position about halfway between the frog and the point pivots.  Unless a wheel had a tread almost half an inch wide, or is turned sideways, it simply cannot cause a short in the area of the gaps or the frog.  And since the point rails and front half of the closure rails are now the same polarity as the stock rail, no short can occur there.  A second advantage is that the point-closure rail power is more reliable, since it doesn't depend on the point contacting the stock rail.

Entering a switch from the frog end against the points will always cause a short, the only question is exactly where.  I power single-ended sidings from the frog (no output gaps), so sidings are dead if not selected by the point position.  If this isn't desired, a second set of contacts can control an isolated foot or two of the inside rail leading to the frog on each branch, as an automatic stop.  Unrealistic maybe, but keeps the switch from being fouled, unless backing up.

The important thing is power district circuit breakers.  A DCC supply usually has a circuit breaker, but it may be too slow, such that the high current flow into a short can cause damage.  I was trying a new BLI engine on our club's Digitrax system which has no external breakers.  After running awhile, it stopped, and I stared in disbelief as smoke poured out from the first driver area.  Apparently a bad insulating sleeve, and resulting in a melted driver.

A good power district breaker such as a PSX is a must in my book.  It shuts down very quickly, and does not expose the short to more than brief test pulses until it is removed.  The PSX also works OK with QSI and similar sound decoders with high in-rush currents.

Hal

 

  • Member since
    September 2006
  • 776 posts
Posted by wabash2800 on Friday, December 18, 2009 8:25 PM

I'm using Peco code 100 Electro Frog turnouts in a hidden staging yard as they are bullet proof. I didn't do any special wiring but, of course, insulate rails when necessary where turnouts face each other. They are power routed so if I accidentally have a turnout thrown against my train, the train will not go. I know that many recommend rewiring the electro frogs to make them safer with DCC but I'm going to chance it with a good circiut breaker.  (I do, however, have the frogs insulated and powered on my Fasttrack turnouts.) I like the spring loaded points and the fact that my staging yard operator can throw them with his/her finger tips. The downside to me is that they are a tad bit expensive and sometimes I have to cut them down to get them to fit in a paticualar track arrangement. Also, I don't like the insulated rail joiners they supply as sometimes I have a hard time getting them to affix to the rail ends correctly. It sounds whacky, but I plan on putting LED's btw the rails in the yard throat in this particular staging yard so the staging operator can tell in an instant how the tracks are aligned. (Trains don't stop on the throat and the track arrangement is complicated.) I haven't decided if I'll use DCC to power the btw the rail LED's or add Caboose Industry switch stands with contacts and a seperate power supply to power them. I'll do the former if it is not an issue. If you don't like the spring loaded points, you can easily remove the springs or strech them for less resistance for a slow motion switch machine.  But, where I've used a Tortoise, for example, I left the springs the way they were and just used a larger  diameter acutator wire. I like to hear the points snap in place even with my Tortii. If you are operating state of the art diesels with normal length wheel bases, you won't have any problems with the Insul frog turnouts. But with steam, especially the older brass imports without wipers, the insul frogs can be problematic. These locos wired through one side of the loco and the tender,  require more pick-up with the way they are wired. A little off this topic but a while back I visited a friend who had converted his layout from DC to DCC. Anyway, my friend who will remain nameless here had cut gaps in his Atlas turnouts that have plastic frogs! He thought that was necessary for DCC...Arghhh.

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!