Not sure how the rails mechanics are, but you could get started by creating maybe Path Nodes or using Bezier curves? and also, this might be an advanced topic for you if you’re entirely new. Learn Bezier Curves, Run Service, Userinputservice, and a lot more to get what you’re asking for! 
How To Create Bezier Curves | Roblox Studio Tutorial - YouTube
How to use TweenService in Simple Terms - Resources / Community Tutorials - Developer Forum | Roblox
UserInputService - Roblox Scripting Tutorial - YouTube
RunService (Heartbeat, Stepped, Script Context) - Roblox Advanced Scripting #24 - YouTube