Here's a link to a thread that might be of interest to the Nn3 modellers. It's in the N & Z topics due to multiple interest but just as well belongs here, I guess. Code 40 Track for Nn3 or Z including flex tie bed and Rokuhan turnout adapters. Hope it's useful.
A short video with more in this thread link.
https://www.therailwire.net/forum/index.php?topic=46808.0