I didn't mean to set off any worries about the ZW-L and Proto-1; the known problems were with chopped-wave transformers from the 90's and early 2000's. These units were designed before PS/1 came out. The early Z750 and some of the Lionel and MRC units were in this category, and the K-Line Power Chief would work with some PS/1 engines but not others. Check out the Mike Reagan video. I seem to remember him saying that the ZW-L was compatible with PS/1, but I'm not sure. There was a big thread on this forum about the video and I think some of those who posted did comment on using the ZW-L with PS/1. I can't say anything about it from personal experience, since I don't have a ZW-L. If you want to be absolutely sure, ask Lionel customer service. I'm sure they will know.
I will admit that I am slightly cautious minded in reading Southwest Hiawatha's post elsewhere in this thread indicating the chopped waves could damage PS1.0 electronics, so I 'm not sure how much I may tempt fate here. (or at least maybe I'll try it with a lesser engine as a test bed)