Procedural track uses track parts from a mesh library to construct a track. Of more interest to Trainz users is its ability to have moving points in a junction/turnout so you can see where the track will take a train. Procedural track takes full advantage of LOD (level of detail) to reduce polygon cost. It also supports seasonal track (snow).
Some of us are still waiting for this approach to permit diamond crossings or similar.
You can read more about in the Trainz WiKi but that doco is intended for content creators.
