I'd like to add a light to a simple tender, that only comes on in reverse. In DC, that would be simple. I AC, I expect it's impossible. Specifically a Lionel RC set. Am I correct? If not surprise me.
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I am not familiar with the set. If the tender has the reverse board in it you simply tap off the motor circuit. You can use and LED with a resistor and diode or light bulb. For the light bulb a simple diode will block reverse current so it only goes on in one direction.
Dale H
Dale, thanks
Its got a speaker in the tender. There is one board in the engine. I will probably just go with marker lights.
If you don't mind running two extra wires in the tether, you could do what Dale suggests, I suggest an LED for the task as it'll light at a lower current and slower speeds.
I'm assuming this is conventional?
You don't need to run extra wires. The draw bar has a 4 wire construct like a phone jack. Since only 2 used for the speaker you could use the other 2 for a light, possibly driven off the motor with a diode so it only lights when in reverse.
Or, there may be a port on the engine board that has that output. Time will tell. G
Not knowing what all is on the locomotive, I was guessing. If there's extra wires, it's even easier. The model wasn't really specified...
You really need to tap the DC motor circuit for a directional back up light. Neither motor lead is grounded to the frame. For marker lights you could use the frame ground of the tender and a wire from the roller.
Dale H
Yet another reason to know exactly what we're dealing with Dale, you are 100% correct. We're just guessing here. 
First. Thanks again for the lively discussion. I'm home from work and catching up. It's the rc Polar Express plus, running on 18Vac dcs. I say plus, because I also have the conventional loco. The conventional tender has rollers. I'm going to swap the trucks over, so I will have tender power. My only marker decision is what size led and whether they should stick through the shell. Evans designs seems to have a small led, with what looks like a nub. I am going to order them and drill holes the size of the nubs. Better ideas that don't involve repainting or remodeling welcome.
That's an interesting idea, about tap the motor leads into the other 2 wires on the drawbar. I'll pick a bulb like the 5 to 13V that runs on dc.
I will look through Lionel parts to see if anyone has a lens that will cover a hole to look more like a reverse light.
That's an interesting idea, about tap the motor leads into the other 2 wires on the drawbar. I'll pick a bulb like the 5 to 13V that runs on dc.
I will look through Lionel parts to see if anyone has a lens that will cover a hole to look more like a reverse light.
Running on DCS? Is this a Lionel or MTH locomotive? What's the exact model number?
John. This is the new RC version of the Lionel Polar Express. It only needs 18V on the track. That 18V is supplied by my DCS system
John. This is the new RC version of the Lionel Polar Express. It only needs 18V on the track. That 18V is supplied by my DCS system
OK, I don't know what is available as far as voltages or backup indications with that one, I've yet to take one apart.
I have 1.5 volt signal relays that I use in other uses, a couple of diodes pairs in series with the motor and one of those relays would allow you to sense reverse. The neat thing about the relays are they are polarity sensitive, so they'd only pick up one way.
He did state RC early on and from following some of his other post I new he had the PE RC.
The frame is plastic and no pickups on the tender of this model. So as I stated the Motor lead is the way to go. G
Well, you're just much smarter than me George. 
I don't know if I am smarter, but I do try to read all the post. G
Originally Posted by Marty R:
First. Thanks again for the lively discussion. I'm home from work and catching up. It's the rc Polar Express plus, running on 18Vac dcs. I say plus, because I also have the conventional loco. The conventional tender has rollers. I'm going to swap the trucks over, so I will have tender power. My only marker decision is what size led and whether they should stick through the shell. Evans designs seems to have a small led, with what looks like a nub. I am going to order them and drill holes the size of the nubs. Better ideas that don't involve repainting or remodeling welcome.
That's an interesting idea, about tap the motor leads into the other 2 wires on the drawbar. I'll pick a bulb like the 5 to 13V that runs on dc.
I will look through Lionel parts to see if anyone has a lens that will cover a hole to look more like a reverse light.
That's an interesting idea, about tap the motor leads into the other 2 wires on the drawbar. I'll pick a bulb like the 5 to 13V that runs on dc.
I will look through Lionel parts to see if anyone has a lens that will cover a hole to look more like a reverse light.
Originally Posted by GGG:
He did state RC early on and from following some of his other post I new he had the PE RC.
The frame is plastic and no pickups on the tender of this model. So as I stated the Motor lead is the way to go. G
Originally Posted by gunrunnerjohn:
Well, you're just much smarter than me George.
Originally Posted by GGG:
I don't know if I am smarter, but I do try to read all the post. G
Don't worry John, if George read all the posts, he would have seen, I'm going to get tender voltage from the conventional tender trucks.
Thanks again guys. Time to buy some parts
I did read that Marty, but now you won't have the whistle on your conventional engine.
Why not just bring the AC in via the other 2 pins, then you can do what you want in the tender with a small circuit board. No truck parts required. G
Originally Posted by GGG:
I did read that Marty, but now you won't have the whistle on your conventional engine.
Why not just bring the AC in via the other 2 pins, then you can do what you want in the tender with a small circuit board. No truck parts required. G
My thought on the tender, is that I would do both swap the trucks and make the connection. wont this help with pickup? Maybe I will leave pickups alone and do as Dale suggests. As to the conventional. I am keeping it , in case The RC fails irreparably, but intend to run only the RC, with the nicer conventional shell. I will chew on this, As I'm not taking it off the track before this season is over.
