Originally Posted by rcf0924:
I have another transformer that provides variable DC up to 14 V and fixed AC of 18 volts for accessories. I want to start by trying the 18 VAC to to my first fixed voltage plug.
It sounds like you want to use an HO power pack to power your switches. If this is the case, it will likely have enough power to run maybe just one or two switches, if that. Check the output rating - an 022 switch with a controller will draw ~ 12-14 VA at 18 volts before you even hit the switch lever.
Originally Posted by rcf0924:
Do I need to run a wire from the other terminal of the transformer (they are not labeled + or _) to the track? Would that connection be made with a lockon to the outside rail that has no connection with the power feed lockons?
Yes, the power supply will need to reference a return to complete the circuit. A connection to clip "2" on a lockon is fine.
Once you do that, realize that that connection can actually be made in any of several places, and clip "2" is "common" to many parts of the layout, including anything connected to the outside rails of the layout, for example the center binding post of a 022 switch, the common/outside rail connection to the transformer, the left/#1 post on a UCS/RCS remote track, and many more.
So in actuality, an extra lockon is not necessary, just the connection that duplicates/parallels that connection point.