One of the key parts of my model, as mentioned, is the Quintette Tunnels near Othello. Usually with tunnels model railroaders settle for nice detail at either end but otherwise leave it open (and accessible) and un-sceniced on the inside. There’s good reason for that – a) you never see it anyway usually and b) you can rescue trains. Another thing modellers usually do is ‘compress’ tunnels to a lesser length than they would be in full scale. The objective is to give you the impression of the tunnel without taking up too much room.
Well, I’m not that kind of guy. The third tunnel in this scene is a really cool 405 footer with a concrete portal at one end, and I was determined to scale it exactly, but also to provide a viewing portal through the side to see the train. That meant needing to scenic the inside of it, including some details of the concrete ‘sleeve’ inside. And that’s what I set about doing here. I ended up breaking the tunnel’s foam segments apart, building the concrete sleeve and detailing it, and then sandwiching it all back together. I created the rounded roof by getting a piece of wood dowling (about 1.1" diameter to scale correctly, taping sandpaper around it and then rubbing it (get those filthy thoughts out of your mind people!) along a piece of foam until I had a concrete roof.