Rail Post

The Rail Post is an upcoming railway item in Astroneer. It allows for the creation of rail lines, and can be used to recall Rail Engines to it.

Source
Rail Posts are placed from a.

Uses
Placing a Rail Post within range of another will connect a rail line between them, deforming any terrain that might be in the way.

Rail Posts may be placed on any terrain, allowing for placement on walls and ceilings of caves.