YouTube creators have documented "Full Walkthrough" solutions for notoriously difficult "Monolith" and "Nova" stages.
While .rar is a standard compression format, be cautious if you downloaded this specific file from an unverified or unofficial source. Large archives of games are often used to distribute: Cosmic-Express.rar
Advanced stages include portals that warp your train across the map or multiple layers of tracks. Cosmic-Express.rar