Help w/ automatic switch wiring

Classic Toy Trains Forum
1

I have 2 left hand 5121 switches. Both are wired to prevent derailment.

I want to have both of these switches change automatically as either train approaches switch #1; Train A on the spur, Train B on the main.

In other words, if switch #1 opens for the main, switch #2 opens for the spur. Conversely, if switch #1 opens for the spur, switch #2 opens for the main.

An old Lionel instruction manual shows how to do this for 022 switches. The manual uses a left and right hand switch for an oval within an oval. It looks like the diagram wires poles 1 to 1 and poles 3 to 3. Nothing is numbered in the diagram, so I am not sure.

I tried 1 to 1 and 3 to 3 with no results - good or bad. Can this even be done with two 5121 switches? Or does it have to be a set of left and right hand switches? If it’s possible, how do I wire it?

Thanks,

Charlie

2

I dont know about 5121 switches but I do it with about a dozen 022 switches, doing what you describe.

You dont have to have a right and a left, just doesnt matter. if 1 to 1 and 3 to 3 didnt work, switch it to 3 to 1 and 1 to 3.

3

I tried that. It seems to throw one switch or the other as soon as the wires touch the poles, but it keeps power running into the switch after the switch throws. With both wires hooked up that way, both switches stay hot.

Maybe it has something to do with the common (pole 2?)?

4

The problem is that the terminals are different between the 5121 and the 022. The 5121 terminal on the metal plate, closest to the switch machine, is the common terminal, not the middle one as on the 022. So the terminals to connect together to get the turnouts to throw in the synchronized way you want are the other two. I don’t understand your arrangement; but there are only two possibilities, so you should be able to get it to work right one way or the other.

5

Thanks, Bob. That did it.

Charlie

6

Good work, Charlie.

One place where the wiring trick that you are using is particularly useful is a crossover (not a crossing, which Lionel insists on calling a “crossover”). The two turnouts are always used together; so it makes sense to wire them together and to throw them from a single controller.

7

Yeah, I needed this to run two trains simultaneously. The section of track between the switches is common for both trains and just past the controlled block for one of them. Getting one train across the common section and off onto its spur and throwing the switch back for the oncoming second train was a little harrowing. Especially since some of my locos don’t run and the same speed.

I still have my hands full, but not worrying about the switch is a relief.

Thanks again,

Charlie