Luther,
Whenever I add an engine I do so with only that one engine on the track. Yes, it takes a few minutes to get all the other engines off the track, (up to 8) but I find it to be a good idea to do so. I also remove any caboose I have on the tracks. For some unknown reason Atlas caboose seem to also impact my ability to add a DCS engine.
I find it easier to add DCS engines on the WIU than on the remote. I have basically stopped using the remote with the advent of the wi-fi app. It's great.
I'm sure some will think I am foolish, but I know this, it works, and that's all I care about.
John