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Big_Boy_4005 posted:
Arnold D. Cribari posted:

Stan, are you Stan Roy who was featured in the McComas and Tuoy 6 video set, and who had the record for simultaneously running the most O Gauge trains (maybe 27)? 

I can't help but think that you are because of your knowledge about relays. Arnold


An interesting question Arnold. You must then know that I once tried to challenge that record, if you remember volume 6. If you don't, watch it again.

Of course I remember that, Elliot. I believe you said on that Entertrainment video that you were up to between 15 to 20 trains running simultaneously, and you warned Stan that you were going for his record. 

Earlier this week, on another Forum thread, I mentioned that you said on that video how trains kept you out of trouble when you were a teenager, while others were getting into trouble.

What I remember most, Elliot, is the sheer joy for trains that you expressed on the Entertrainment video, which you continue to express on this Forum. That joy is infectious, bringing much joy to our Forum friends and many others who saw, and continue to see, the trains you run. Arnold


4 channel relay module 12V set to LOW trigger trolley rev1

I think I might have a functionally identical 12V DC 4-relay module like the one you identify from Amazon.  I got mine on eBay for less than $3 shipped.  In any case, this shows how to perform the latching relay function using non-latching relays.  Note that only 3 of the 4 relays on the module are used.  This assumes your switch machine operates by momentarily applying the outer-rail voltage to the SwM A or SwM B terminals to fire the appropriate A or B solenoid coil.


I don't know what track system you have, but I wired up MTH Realtrax sections and a Realtrax turnout-switch.  The short sections of track with white-paint labeled IA, IB, IC in the photo below are isolated outer-rails.  You can't see it in the photo, but the outer rail was cut with a hacksaw to create the mini-island of outer rail for bench testing/simulation of insulated-rail triggering.

alternating trolley using DIY latching relay

And here it is in action!  

What I tried to show is the elegance of the latching relay.  That is, you can have "dirty" track with intermittent trigger contacts and resulting multiple triggers - the latching function cleans this all up.


Images (3)
  • 4 channel relay module 12V set to LOW trigger trolley rev1
  • dual%2520coil%2520latching%2520relay%2520method
  • alternating trolley using DIY latching relay
Last edited by stan2004
OddIsHeRU posted:

Gentlemen, we have this same electrical requirement in modern pipe organ consoles where each stop key or knob has on and off solenoids built into it. A push button t will move the stop to the other position from what it currently is. Even if you manually move the stop, the logic senses what to do next time you press the button. The circuit boards (called “Reversibles”) (12v DC) are available. Check with your local pipe organ installer or service technician for sources.

I like it. Never thought of it, but I like it.

Stan, just got back from an internet-free weekend (wife's idea for some quiet time) and I saw your GREAT drawings! FANTASTIC!!!! I really owe you many thanks. I am running K-line switches so I can make my layout look just like yours. A few questions -

I am reading, for example 1A is to the insulated rail trigger. Does that mean I leave the insulating pins in the switch?

You are showing a "box" attached to the switch for power with additional yellow leads attached to the inside rails at the ends. Why both?

I can't tell where the wire attached to the green alligator clip is going.  Sorry for all the questions, but I am electrically dumb.

If you feel like it, please send me your address as I would to send you an appreciation gift. I am also a woodturner so free free to ask.

So here's where my ignorance of K-line track rears its ugly head!  Someone more knowledgeable can fill in the blanks but here's my attempt at your questions.

isolated rail trigger

As I understand it, the K-line insulator pins allow you to create an isolated trigger section in the outer-rail.  Or, it could be the last section before the bumper for the A, B, and C sections.  I believe the idea is the K-line insulator pins provide structural integrity without electrical connection.

k-line switch

I figure this photo of a K-line switch I dug up on the web represents what you have.   There are 3 terminals which normally go to the manual lever controller.  As has been discussed earlier, one of the 3-terminals is the outer-rail (common power connection).  It's the other 2 terminals that I'm calling SwM A and Sw B.  That is, you momentarily touch SwM A to the outer-rail and the switch snaps to the A direction.  Momentarily touch SwM B to the outer-rail and the switch snaps to the B direction.  I'm sure if I searched harder I could tell you which of the 3 terminals is the outer-rail terminal and which are the SwM A and SwM B terminals...but I'll leave that exercise to the student. 

As to the yellow wires (alligator clipped to the outer rail in my photo), this is an artifact in that the MTH Realtrax section do NOT internally connect the outer-rails together.  I don't know how the K-line track sections are wired.  So the Realtrax, I simply added the yellow wires so that BOTH outer rails everywhere on this contrived "layout" are connected to the transformer common.  Of course everywhere means everywhere except the isolated trigger sections IA, IB, IC.

Again, showing my ignorance about K-line switches, when you ask about insulating pins to the switch section, my understanding is this has to do with anti-derailing.  In theory you will never need the anti-derailing function in this application because the switch will always be set to the proper position!  So if I understand your question (which is itself a question!) I don't think the switch's outer-rails need to be isolated.  Someone please enlighten us if otherwise.

The green alligator clip is just an alligator-to-alligator jumper cable from IA at top of photo to the relay module at bottom of photo.

Let's just get this contraption working and that will be appreciation enough!  


Images (2)
  • isolated rail trigger
  • k-line switch

Richard, as I said in an earlier post, you MUST leave the insulating pins in the switch, even though the non derailing feature isn't being used in this application. The lack of pins will cause the switch motor to malfunction. The trigger sections will also need insulating pins or gaps which won't accidentally close up. These statements are true regardless of track brand being used.

What brand of track are you actually using?


Last edited by Big_Boy_4005

No problem Richard, it's back on page one near the bottom.

Sorry for using different terminology by saying "trigger". I just mean the three insulated sections that Stan has named IA, IB and IC in his drawing. I say trigger because those insulated sections trigger the events critical to the operational sequence of this layout. From an electrical perspective they are insulated sections, from a logic perspective, they're triggers.

So, what brand of track are you using?

Very good. I suggest that before you do any serious wiring on this, that you test the trolley on the switch. I'm slightly concerned that the trolley being light weight, and the switch being a little rough, it is possible it could cause the trolley to bounce and even derail. If the trolley passes this test, then it's safe to really get into this project.

I'm not sure that Lionel ever really intended for this unit or its little brother the gang car to go through switches. All of their track designs, just used straights, and maybe a couple curves between bumpers. This level of creativity seems to be a little beyond their vision.

Big Boy, I have already tested the trolley on my main track running it against two bumpers to test the bump-&-go function. It worked even at a fairly low speed. Waiting for my wife to leave on a week's trip to visit her cousin so I can put it together on the test board I have already set up - that way I can manage my honey-do list she always leaves me with.

Bad habit of mine from my old industrial engineering days where I tested prototypes before putting anything into production. Can't wait to put all the great plans and suggestions from you and Stan.

Stan2004, I didn't want you to think I took all your great advice and then dropped off the planet. About a week after you took the time to lay things out for me, I got T-boned by someone running a red light. Been out of the hospital for about a week - punctured lung and broken hip the worst of it. Needless to say, I won't be getting to put the trolly switching system into play for a few months. But again, MANY THANKS FOR ALL YOUR HELP!!!!

Very true. But with the exception of the the trolly area, every thing is in place and I was starting the scenery details. But fate is funny. A friend picked up an 80" x 28" N gauge layout as part of a package deal at a yard sale. He didn't want it but had to take it to the other items he wanted. So he gave it to me. Track laid and hills in place. I don't like the layout and want to change it around so now I have the time to play with track configurations. 

Yeah, what Stan and John said. It'll be good therapy when you are up to the task. I suspect you'll feel up to that long before you feel like real work. On the other hand, if you need to go under the layout to wire this up, it could be a while.

I hurt my left knee in November, and my right knee in May. I haven't been under my layout in about a year. It's not like there isn't work to be done under there. I'm just getting back to the point where I can walk up and down the stairs, but getting down on the floor and more importantly getting back to my feet, is the next hurdle. I've kind of been afraid to try.

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