Ladies & Gentlemen,
Some of the P1 engines did have problems with the smaller Z transformers, if you still run P1 engines, they run quite well with old Lionel ZW & KW transformers, just remember to use breakers between the old transformers and the TIU. Replace all the batteries in the P1 engines, with BCR's and have fun running your P1 engines.
PCRR/Dave