Here is a list of all related documentation pages:

Changelog railOmniverse Extension (omni.rail.core)
Reference
Tutorial 0: First Steps
Tutorial 1: Get Started
Tutorial 2: Rail Anything
Tutorial 3: Assemble a Train
Tutorial 4: Build a Locomotive
Tutorial 5: Import a Track System from EEP
Tutorial 6: Steering a Locomotive with Omniverse Action Graph
Changelog railOmniverse Schema Extension (omni.usd.schema.rail.core)
railOmniverse Schema Extension