Railrunnin,
Paul pickup a original PRR Brunswick Green Williams GG-1 and use it as your primary running engine on your Christmas layout, they run for as long as you like every day, all day long. I also have an original Silver EC44 Williams of the same quality, I would use that on your other track. Use your PE only when you are around to watch it, in reality they are not a high quality run all day engine.
These old Williams GG-1's and EC44's are simply high quality run all day and night engines.
PCRR/Dave