“Unrailed has just been announced for Steam Early Access and will be hitting the platform on Sept. 9.”

Source.

This is a co-op game where players have to build a path for a train to traverse an endless world, players will be given tools to help the train moving, but the train will move, no matter what is the obstacle, at the end of each level, players can upgrade their train by adding wagons, changing the engine, and more.

Once the players are done, they are sent to the previous stage, as more section of terrain are added each terrain addition, players will meet new challenges, a fiery magma field, pools of lava, and build the appropriate type of track to cross it.
The game will have a dynamic weather system, like day to night.

The game is highly based on communication, players will have to split up the work between themself, hoping to not bodyblock each other.