Create an 8-12 second cinematic VFX aerial-control video of a mountain railway sequence. Begin with an ultra-wide drone view above bright snowy peaks, then dive smoothly toward a passenger-free scenic train entering a mountain pass. A controlled snow-slide VFX wall releases far behind the train, moving through the valley as an environmental effect rather than a real emergency. Keep the train, track curve, tunnel mouth, snow plume, ridge line, and camera direction consistent. The camera skims parallel to the rail line, arcs wide enough to keep both the train and the moving snow field visible, then climbs rapidly into a final reveal showing the pass behind the tunnel filled with drifting snow mist. Use realistic alpine daylight, crisp scale cues, stable drone motion, readable distance between the train and snow, and physically plausible snow flow. Avoid visible passengers, injuries, panic, rescue scenes, derailment, collision, real disaster claims, news footage styling, logos, readable text, warped train geometry, teleporting tracks, broken tunnel perspective, impossible snow direction, or camera cuts that reverse the travel path.