In one of my biggest follies, I decided to build a curved, almost 3% graded tunnel, without prior tunnel experience. Attached are pictures.
First, the roadbed for the track and footings for the sides were poured and reinforced with 3/8" rebar. Then track was screwed down to the roadbed and the sides were checked for sufficient clearance using my largest cars - Aristo Streamliners.
Originally, I had metal strapping to support the roof. That didn’t work! Then air mattresses were blown up for support [track wasn’t supposed to make hole in air mattresses]. Finally, in desperation, 10.5in 2x4s were wedged inside to hold up the estimated 140lbs of concrete.
Grandson Christian, runs the Mikado w/ “Where’s the Beef” stock car & reefer consist [CCW] on Thanksgiving day, through the tunnel, while grand daughter Kelsey, runs the Scientific Toys train on the inside loop [CW].
To me it seems to be overengineered to hell; however the end result looks pretty good, to me.
I have several tunnels and none of them are anywhere near as heavily built. My main one is 2.8 m long and is a double decker.
Have you run your longest rolling stock through and even more important have you any idea of buying longer rolling stock, you may have trouble with overhang etc.
Tunnels are good stuff mate, i love my trains disappearing into them and coming out somewhere else and they are easy to do, i have used a 220 mm 9" storm water pipe with about 150 mm cut out of the bottom to take the track, very easy. However you may have a problem with the most surprising locos ie ones that have a low outreaching piece. the the loco may ride up on the lower sides and stall.
pimanjc;
I like your construction technique. Now for the big question. Does the tunnel have an ultimate landscaping purpose or is it there simply to have the train disappear and then reappear somewhere else? Hope you put in a water drain or two. My tunnel was built much like yours, and now has a waterfall on top of it.
Nice tunnel , does seem like you over engineered it a bit but you had fun and it seems to do the job . With mine I cemented 16"x8"x2" precast stone walkway bricks side to side and then cemented same on top for the roof . The wing entrance walls are the same brick but cut with a power saw and masonary blade . I built the tunnel to clear double stacks.
That looks very interesting, the snow scene i mean. Being in the tropics we don’t get much of that sort of thing. Temp here today will be 31 dg C, too hot to even wear socks.
