Needed three tunnel portals for my new N Trak module. Those available did not quite fit the bill. I needed them to be on a slight radius and clearances would be tight. The double portals looked too wide and the singles too narrow. Here I built one using styrene on the order of Woodland Scenics concrete one. Made to a better width for my purpose. I then, naturally, made a rubber mold of that and cast up the three I needed. Not visable in the picture is the year "1948" cast into the portal lintel. Cold stamped the styrene to provide the negative. They look great and I found that it looks better cast with "Durham's Rock Hard" putty than the plastic resin.