To help simplify this, you can remove TIU from layout and test engines in conventional. If they run chances are the issue is the TIU. We already know this since at least 2 trains ran fine at the shop, but not on your layout.
As far as TIU you do know your address and your remote talks to it. Now how about all your connections are they fine. Is the track clean, are the engine wheels and pickups clean.
Build a simple circle on the floor and connect your TIU to it. Use one train that worked at the store. Add it see if it works. If so do a signal strength test.
If you getting power to the track and the engines staying quiet and they have power, they are seeing a DCS signal. It may not be strong enough to add or operate the engine, but they see it. The TIU may need repair.
BUT I have seen plenty of trains left sitting that have dirty wheels and poor pickup continuity that they do not get track power. That is not the issue with the F-7 since the ran at the shop, but could be the issue with other trains.
Also, if PS-2 you need to make sure batteries are good and fully charged. The conventional test will show it they are. If no shutdown sounds when track power turned off the batteries weak or dead. G
