Russell: Absolutely correct on your initial observation. Smell is what once led me to an uncoupling track, the button for which had stuck on and which was fast melting the track.
As I noted above, I run 3 AIUS from a TIU powered by an R-S unit, BUT, I have no accessories connected, which means only one switch relay will be triggered at a time.
I have no idea what the draw is on an AIU relay coil. But speaking of AIU relays, I am in the process of replacing all of my old NJ International switch motors. They make a really bad spark upon break. I have them wired through the side contacts, so that the AIU relay points don't take the full brunt, but there's always one or two that don;t break properly. I recommend never using AIU relays to directly control solenoid-activated switch machines. Z-Stuff's DZ1000 draws under 0.1 amp, and breaks internally, so all 45 switches will shortly have them.
I would use the accessory terminals for uncoupling tracks, but sooner or later I'll hit the wrong button on the remote and they'll stay powered on. I wish they could be set & locked .to either toggle-on-off or intermittent.
