Cattle creep
This stone effect OO scale kit makes up in to a cattle creep. How you space between the sides will determine if it is single, double, treble (or more) track width.
This type of structure would let cattle cross between fields under a railway line. It could also be used as a culvert for watercourses to pass under the railway.
The wing walls are included, and the kit needs glue and paint to finish as required. Although OO scale, it could be used in other scales too.
What can be achieved is shown in the picture.