Engineer Joe/Gregg,
Thanks for the input. I think I will try this again using a short test track I have rather than do it on the layout. And you could be right about the batteries, although I did do a mass re-charge exercise within the past year and each of the engines do get run at least a couple times a month for a few hours.
I just did a whole layout signal test with my current TIU (rev H.2 software 5.0) a couple of days ago and everything was fine. Power is Z4000.
I'll post the results using a short test track later.