I'd say, the ZW's are doing what they are supposed to do - protecting.
The "trippers" are the passenger consists. Too many light bulbs, I concluded, during a personal experience running my layout.
In my limited personal experience in this regard, I have used these 5 ZW's (10 trains altogether; 2 per ZW, using only the two large handles on each for trains,) since inception of the layout in 1995. The only time the ZW's have given me any grief was when I tried to run (TMCC) TWO (8-10car) passenger trains on the same track. The ZW responsible for the initial trip-out went out after, approx. 3 minutes.
Then, I changed both trains over to a different ZW; same result - tripped-out.
It wasn't the two steam engines on the same track and ZW arm that were pulling those passenger consists that seemed to be the critical factor, because as soon as I changed one train over to freight, no problem with tripping.
My conclusion? Though the lighted windows seem innocent enough, they apparently add up to quite a drain. Thus, they trained me 
and I modified my behavior to not run two passenger trains on the same ZW handle.
FrankM, Moon Township
P.S. For more particulars, I refer you to my betters, above, like CW Burfle. Those guys know lots of stuff. I just want the trains to move and look good doing it,; beyond that, my usual reaction is "Huh?'", and I call over to the house a specialist (he's the guy who designed and installed that ZW cache, as well as wired the entire layout, with connections every 4-6 ft. along all the ten independent loops.
