ByronB - I experienced the same problem even though I carefully read the Manual and followed the directions step by step. I also reviewed a recent Post on this Forum (very similar to yours) by Steims (dated 15/03/20) entitled "TMCC F3 ABBA Lash-up Trouble, Needing Help" the replies to which enabled him to resolve his problem. In addition, I watched an informative Video on YouTube.com entitled "Using Lionel TMCC to build a Lash-Up" that you might find helpful.
Good Luck!