Adding Indicator Lights to Turnouts

One of the things I've wanted is a control panel that will give me an LED indicator on my control panel, and the ability to have an LED-based signal at the actual turnout (particularly for turnouts where you won't be able to see the points).  I'm apparently not alone as this seems like a fairly frequent question from others on the various forums that I visit.

One of the happy 'discoveries' I made is that there is a really easy way to add turnout indication to switches that have powered frogs.  As both my new Minitrix switches (for the yards) and my Kato Unitracks (mainline) both feature powered frogs, I was saved from doing a lot of extra wiring that would have turned out to be somewhat unnecessary.

Credit really goes to several folks on the NScale.net forum where there is a whole forum on this topic of turnouts and signals.  I was inspired to test this out as several users of Peco switches (with powered frogs) mentioned this method.

The good news it that it works great if you're using DCC!  The constant voltage to the track from DCC, the changing polarity of the frog, and the low power consumption of the LED's is a great combination for adding switch indicators that I wanted in a fairly easy manner.

First, the indicators or LED's that I am using are pre-wired red and green light indicators which feature 3 wires; a common, and a wire each for the 'red' and 'green' lights.  I expect that this wiring method will work with any 3 pole LED as long as the proper resistor is installed to the common wire (or 'lead').   And, it goes without saying, pretty much any LED you put on track power will need a resistor!

The biggest challenge was where to solder the wire to the frog.  Its imperative that you don't solder the wire anywhere the wheels or cars will run, and unfortunately the unique design of the frog leaves few options.  You might be able to solder onto the end of the inside 'rerailer' rail which shouldn't impact the performance of the cars rolling across the switch, but that still doesn't seem great (although see below).  Isn't there a better place?
In fact, there is a better place to wire to the frog with Kato's #4 switches!  The secret is to solder your common lead to the 'frog power' screw on the bottom of the switch!  Yes, this does mean you won't be able to unscrew it because all this solder will gunk up the screw, but I figure this is not something I've ever going to change anyway.
Attach the 'red' and 'green' leads to the outside rails of the switch. Add track power and...VIOLA! Switch lined for through...'green' indicator!
Flip the switch to the diverging direction and the 'red' indicator shows!
By the way, the above indicators are from a company called "Berko" which are made in England and which I picked up on my recent trip to the UK at Gaugemaster.

As mentioned above, I'm also using Minitrix switches in my yards, where I also want to have turnout indicator lights at or near the switch.  I'm also using the versions with the powered frogs (14938; 14939) otherwise this wouldn't work.

The Minitrix switches, unfortunately, don't have a convenient 'secret compartment' like the Unitrack versions, so I was reduced to good old fashioned craftiness.

The best possible choice seemed to be to solder the common lead to the very end of the inside of the 'rerailer rail' (I'm sure it has a proper name) which I accessed by drilling a very tiny hole (only large enough for 30 gauge wire).
This was a bit nerve-wracking as I wasn't entirely sure where or if this location wouldn't interfere or contact some of the other conducting surfaces of the switch.  Fortunately, its a good spot.  Although I was careful to keep as much insulation on the wire for fear of any exposed wire coming into contact with the big metal plate on the bottom of this switch.   Yeah, that wouldn't be good I imagine.
 Again, soldering leads to the outsides of both of the outside rails....
 And...switch lined for 'straight ahead'....green indicator!
 Switch lined for diverging route....red indicator!
The indicators used in the above photos with the Minitrix switches are from NJ International, and like the Berko indicators above, they are 3 wire red/green indicators.  They are meant to be inserted into the layout and sit nearly on the ground near the turnout.

This project was a huge 'victory' for me.  Again, maybe I'm just dense, but this whole scenario never really occurred to me.  Additionally, in all of my Googling for 'led switch indicators' etc.... I have never seen a solution as elegant as this (except specifically for Peco switches), although I'm sure thousands of folks are already using this technique (and there are probably dozens of brilliant people who've blogged or written about this before!) it somehow escaped me (well, not quite, as mentioned above, what little I know came from the folks who share on the various forums around the net)!  So please....I apologize if I'm overly enthusiastic about the 'discovery of the obvious'!  Of course, this method requires 'powered' frogs and DCC, but that seems to be quite common these days.

The alternative...well, it usually involves a lot of wiring with diodes, capacitors and other stuff that, while I'm quite happy to attempt, can also be more work!

I'm going to continue to experiment with this method and try some other things with these LED's (e.g. adding more distant signals with yellow indicators...or 'flashing yellow'! Whoohoo!).  Hope this post could at least help a few other folks struggling with the same problem I was!


  1. Thanks for the photograph of the wiring on your Kato turnout! Very helpful.

  2. You bet! I hope it helps! As you can tell, I'm pretty excited about this. I had to check with the folks who know more about electricity than I do on the Japanese forum and it seems like this is perfectly fine!