rdunniii posted:If you put P48 wheel sets on a rigid MTH truck block about the only thing you are going to get is a lot of derailments, unless your track work is exceptional. The flanges are simply too small to deal with less than perfect track work unless the trucks can equalize some. Part of P48 is "track is model too". You can use .115 P48 wheel sets and the gauge difference is indeed hard to see. Lee Marsh and MMW are both making their models in both 5' and 4'8.5" with .115 wheels.
Both O Scale Turnouts and Signature Turnouts can make P48 turnouts but the former uses P48 frogs which have a prototypically deep flange depth so regauged .145 wheels will likely derail due to the too large flanges.
Since any layout I make to start in P48 is likely going to be a switching layout, I was actually thinking of buying flextrack, but making my own turnouts so I can use my space to the maximum (e.g. constructing a 24" radius switch for a spur extending out from a curve). It seems like P:48 ready-built switches are very wide in their radius (#6 and #8) and relatively long, which in my opinion is great for mainline running, but less so for short mainlines and switching.
