A masonry single-track tunnel portal with a rounded arch opening framed by neatly cut voussoir stones. The heavy retaining face carries a stepped stone cornice across the top, with angled wing walls flanking the mouth and a small separate abutment block to one side.

The weathered stonework suits a mountain rail line, a cutting through rocky terrain, or a canal bore. It is a staple scenic structure for model railroading, letting track disappear convincingly into a hillside on a layout.

Use it at the edge of a diorama or backdrop to imply depth, and pair with matching retaining walls to line the approach.