Starting Friday off with some good news, the developer of Unrailed! has confirmed a Linux version is currently in progress.
Back in July, the developer actually said on Steam that some of their team are Linux users but they weren't promising anything for the game. However, just yesterday they came back to the same Steam forum post to note "It is in the works :)".
Okay, good, so what exactly is it? Unrailed! is a multiplayer (both local and online) railroad construction game, one that looks like it can get a bit crazy. You have to build across procedurally generated worlds, overcoming whatever is blocking your way.
As you progress you upgrade your train with things like an atomic engine, upgrade your crafting wagon, attach a supercharger or choose from "a vast range of other options". There's even a versus mode for two teams to go head to head which sounds like a huge amount of fun.
You can wishlist and follow it on Steam.