# Wiring MTH cantilever signal to insulated section- need help



## santafe158 (Jul 14, 2010)

I've had an MTH cantilever signal bridge for a long time and it's always been a pain to hook up. Most recently I just hooked it up to a couple of on/off switches so I could control it manually. That worked OK, but I'd like to activate them with the actual train using an insulated section. I don't want to spend the money on a Lionel or MTH infrared sensor and from what I've been reading, I can do the same thing with an $8 relay of some sort from Radio Shack.

There are two sets of wires (one for each signal head). Each has a black a green and a red wire. The black is ground, the Green is for the yellow and green lights and the red is for the red signal. What I need to be able to do, is shut the green light off and turn the red light on, and then the opposite (yellow light's up for a few seconds when power is applied to the green wire before the green light lights up) to change back to green.

Do any of you electronic guru's know what I need and how to hook it up?

This is the signal I have


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## gunrunnerjohn (Nov 10, 2010)

Sounds like a SPDT relay might do the trick. Connect it to the insulated track and power it using DC from an external supply. Use a large capacitor across the relay to give it some hold-up time if necessary. Wire the common relay contact to the power supply, wire the red to the NO contacts and the green to the NC contacts. Wire the black wire to your signal power supply common.

Does it use AC or DC?


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## T-Man (May 16, 2008)

This is how I see it. What do you need to power the lights?
A relay operates on DC. The track is AC. I pulled all the manuals. The tad may work and it comes with a block signal.

The cantilever.

The block with the tad.

The tad itself.

For future reference an itad that you do not prefer. (Infrared)

TO me you need a board to detect it like this one,

I am not sure of a simple was to do it
Theasiest is runnginf the ground through the isolated rail when contact is made but that is only good for one light. Then the relay is needed also the DC current.


OooH I like that talk!


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## santafe158 (Jul 14, 2010)

I think I figured it out. I need a bridge rectifier to change the track power over to DC (the signal seems to work fine off of DC power) for the relay. I can picture how to do it in my head, I just can't put it in words .

This is the site I'm looking at for ideas. http://www.toytrainrevue.com/


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## T-Man (May 16, 2008)

We are interested in the final result. It is an neat accessory.:thumbsup:


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## santafe158 (Jul 14, 2010)

Here's the diagram I found. It's from the "how to build an O gauge layout" video by TM. They were also using the relay to shut track power off so they could have automatic two train operation on one loop. My version will be a little simpler, to just power the signal.









I love the signal, it's just a big pain to hook up. My dad had to do it when we first got it (I was still using O-27 tubular track) using an insulated section and a 157C contactor (I think that was the number). Plus a couple of lockons.

The relay seems pretty straight forward.


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## santafe158 (Jul 14, 2010)

Got it hooked up with a relay and a bridge rectifier. So far it's working great.


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## kursplat (Dec 8, 2010)

so what causes the yellow signal to light and what causes it to time out and turn green?


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## santafe158 (Jul 14, 2010)

There must be circuitry built into the signal somehow. When you apply power to the green wire for the green light, the yellow light comes on for about 10 seconds before turning green.


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## santafe158 (Jul 14, 2010)

Here's a picture of the finished project. My electronics are mounted in the shack at the base of the signal. The signal is screwed to a wooden base. The shack is glued and screwed to the side of the base, and there is a screw and glue underneath the roadbed that holds the whole assembly to the insulated section. It's all one piece. Looks pretty good to me.


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## gunrunnerjohn (Nov 10, 2010)

All's well that ends well.


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## santafe158 (Jul 14, 2010)

Yep, I'm happy . I really had to think about what I was doing to finish wiring the relay, but I finally figured it out. Working good.


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## T-Man (May 16, 2008)

The diagram is from the Toy Train Revue.
The link is here and there is more information there too!


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## plandis (Oct 5, 2011)

T-Man said:


> This is how I see it. What do you need to power the lights?
> A relay operates on DC. The track is AC. I pulled all the manuals. The tad may work and it comes with a block signal.
> 
> The cantilever.
> ...



is that TAD more or less a modern day 153C contactor?


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## gunrunnerjohn (Nov 10, 2010)

Yep, it's just a switch activated by the weight of the train.

Here's the modern way to control this stuff: Lionel 153IR Controller


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## plandis (Oct 5, 2011)

I thought so. I do have one of those IR detectors. nice off delay incorporated also!


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