I have one bank of ZWs for the entire 10-trains-and-1-trolley layout, utilizing one ZW for every two closed-loops, plus a rotary beacon on one of the short handles.
The only time one of the ZWs punked-out on me was when I tried to operate two rather long passenger trains on the same track, which also included several lighted switches in that loop. The ZW blinked-out in short order. My solution? No more doubling-up of passenger trains on the same loop = separate tracks for each passenger train did the trick. We are all living happily ever after.
FrankM
