I have an P2K S1 which is the best looking plastic switcher out there IMHO, but mine stalls sometimes on my Shinohara 30 degree crossings. I've checked the usual suspects, cleaned the loco wheels with MAAS, cleaned the track, etc. Still stalls sometimes. It has a Digitrax N Scale decoder in it DN121 I think. Sometimes just a hitch in it's get a long, sometimes a dead stop. My Atlas S3 and Kato NW2 don't stall at the same places. Any suggestions? It runs fine over switches.
Since I am an HO person, I may be incorrect, but I suggest taking an analog multimeter and finding out the length of the 'dead' portions of the track are around the 'crossing'. Then measure the length between contacts on the loco. That may answer your question