I have found over the years the only thing that works is: HOW MUCH POWER DO YOU NEED X 2 . This works for about 5 years then some one comes out with a ABBA,8 motor engine set. I have gone from set supplied to a 4 amp w/sound ( still used under tree ) to a 10 amp and the last is a 15 amp (a present from my wife). the 10 is used for branch lines and 15 is used for main line operations .
And 4 amps isn’t enough to run your ABBA set? Oh, Maybe not with smoke.
The 4 amp is used under the Christmas Tree with a LGB Snoopy train or a Delton Doozy on a 5ft loop. not much power needed for that with or without smoke.