A shallow fill spline made of brown ballast.
For use under track (align the spline points with the spline points of the track).
Fits narrow gauge track.
This can also be used as a road if no track is used.
Textures courtesy of CGTextures.
A little more desaturated than the brown ballast version to better match some of the brown ballast ground textures out there.
Revision 1: added seasonal support