First, thanks to everyone for responding. I have learned a few things and I appreciate the sharing of knowledge.
I set up a loop of track completely separate from my layout this morning. Hooked up one of the TIUs and did a read and found it. I did a factory reset of it as well as a reset of the hand held. I then brought everything back up, did a read, and found the TIU. Set up variable one and was able to power it up with the hand held. Put one of my PS2 engines on it and was able to add it to the hand held. Everything worked fine. I then powered down and connected variable two to the track and powered it up. Again everything worked fine and the engine responded as you would expect.
I took the TIU and put it back on my layout, reconnected the input and output wires as normal and powered it up. This time everything worked. I was able to re-add the engines that were sitting on the layout and everything worked as it should.
This afternoon I hope to repeat this process with my other TIU except I will rename it to TIU 2 after I get it talking to my track loop. I hope to reinstall it on my layout, establish both TIUs as "super" again so I can swap my engines around on the various tracks they control as I was able to do before.
I still don't understand what caused this in the first place but I am happy that I am making progress in getting things back to normal.
Again, thanks for everyone's input. I find this forum to be both helpful and entertaining and this plus some of the Facebook train groups give one a sense of community in what is often a solitary hobby.
Colin Pratt
