Here a pair of tunnel portals I made for my good friend Nate Goodman (Nato) for use on his layout. Prototypically, these are at Taggarts in Weber Canyon and are further apart. I'm building a 6' module of the Taggarts Tunnels and bridges, so building these solidified materials and techniques for making ones that are spaced correctly for my module.
Here's a photo of the model installed on Nate's layout:
Here's a photo of the prototype:
I used poplar I bought at The Home Depot, taped each portal to my drafting table and used my parallel rule, scored the form marks with an X-acto knife, then proceeded to carve the cracks and broken concrete with the same blade, file and rifflers. Cut the portals roughly with my jigsaw, then finished them to my drawn lines with my cylindrical sander. Glued 'em together with yellow carpenter's glue. Finished by brush painting with various shades of Polly Scale concrete, aged concrete, reefer white, and weathered black.
One of a kind.