30 volts on insulated rails

You do realize that sometimes a meter will give bogus readings on some voltage outputs, especially if they're not true sine wave outputs.  However, the fact that you have 12V and 18 volts running around does suggest they're getting added.

Did you turn off the 12V and see what reading you get?  Could this be simply a phasing issue with the transformers?  Try swapping the orientation of one of the transformer plugs.

I have shut off the RS-1. This eliminates to 30 volts. I get 18 volts from the Z-4000's. If If I shut off the Z-4000's and leave the RS-1 on I get 12 volts on the insulated rail. I can't seem to find why they are connected. I'll check the plug on the RS-1 tonight. The Z-4000's are all in proper phase.

Like it or not both the Z-4000 and Lionel RS-1 set ( One side of relay power supply ) share the same common outside rail when the insulated section is occupied. They(z-4000 & RS-1 ) should really be phased  together.  You may get lucky by reversing the plug on the RS-1 as John suggested.

Sounds like phasing to me, like Gregg and I have said, try swapping the orientation of one of the 115V power plugs.

bogus readings like this?

Are the RS-1 and Z-4000 transformers all plugged into the same circuit in your house's circuit panel? If they're not are they both on the same phase? If the transformers are not on the same circuit and are on the opposing phase from your circuit panel this could cause this. 

Ron

Yep, sometimes it happens.   A load on the output will eliminate any false reading as a rule.  Just a light bulb or two.

Well guys, it's fixed. Thank you Gregg, Gunrunnerjohn & Railfan Ron. The RS-1 transformer was plugged into another outlet. Such an easy fix after spending 2 months under the layout checking 18 devices and untold amounts of 16/2 wire. Plus, my wife asked me at Thanksgiving time if the transformers were phased. I had it stuck in my thick head that the only transformers that needed to be phased were the Z-4000's. I just went upstairs and told her it has been solved. She wants to join the forum.

Thanks again guys. Hopefully I"ll meet you all at Trainstock on Saturday..

We need female blood around, especially those that understand transformer phasing.  How long do you think she'll rub your nose in that one?

And you were right.

You could be powering your signal system with a car battery just as easily.  As long as they are separate systems, it doesn't matter.

The RS-1 adds a little bit more complexity to the mix, if you were using it too for train control.  It is more like a CW-80 electrically and often does not like to play with conventional / sine wave transformers. 

You could be powering your signal system with a car battery just as easily.  As long as they are separate systems, it doesn't matter.

That's true, It's not uncommon to have one side of  DC imposed on the outside rail; I've done it for relays instead of adding bridge rectifiers  to every dc relay.

I not so sure about the RS-1 though, I suppose it's the same idea since only one side of the AC(RS-1)  is imposed on outside rail. Why the high voltage reading?

There was a floating potential(with next to zero current) because there was no common reference point for the two circuits.  If you did measurements with a loco on the control block it would all look normal.  The axles would make the bridge and reference the control rail to the layout common ground.

Anything that interests your spouse in trains, is a good thing. Worth the 2 months work!