Oh, about one foot I’d say…
I told you guys I’m rethinking the entire thing. I’m taking an idea from the Chesapeake Bay Bridge-Tunnel. I figure if it works on the open water for 17 miles, then it should work in Gummy scale for 30 feet.
Much more to follow…
I hope…
With the weight of that steel TJ watch it doesn’t sink and give you an underground railway!!
Kim
I’ve got that covered, Kim. Those pylons are at least 18" below ground level pile driven into the clay, they ain’t goin’ nowheres. I’ll fill the pylons with concrete and set a stainless steel bolt into the top of each for mounting the roadbed. It’s a bold experiment to be sure, but as I said the CBBT is constructed in exactly the same way for the most part. I wanted to add some vertical interest to an otherwise flat railroad and raise the roadbed from direct contact with the ground. I’m hoping my maintenance is easier as well as putting the trains “up on a pedestal” if you will. I’ve had guest come over and say it was a lovely garden but they didn’t see the train. In theory it will be easier to make changes, just drive a new pylon and attach the roadbed.
http://www.cbbt.com/
Follow this link to see what I’m talking about.
That’s a novel idea for a tunnel TJ, get fed up of building bridges and dive through the water to start the tunnel! What depth of water does the tunnel start in? Did they build an artificial island first or ???[%-)]
Cheers,
Kim
They built a couple of artificial islands. Tunnel goes under a 55 foot deep navigation channel. I forget how much backfill over tunnel and under channel, but i think they are separated by about 20 feet of mud. You can play hell with tunnels and pipelines by dropping ships anchors on them (been there, done that!).
Then one time they had a naval supply ship out in the anchorage that dragged anchor in heavy weather and knocked like 3 sections of the bridge out!
If you visit this side of the pond, it is indeed something to see. Really feels wierd to be driving along and see a ship cross your bow, or see one coming and realize it will be passing over just as you will be underneath it! Real disconcerting to a professional mariner the first time you see it!
TJ, are you allowing for expansion & contraction in that steel roadbed? I’d think it could be considerable in our climate!
nice! I like the simulated rust too 
We Southerners are often prejudicially called stupid or slow, even though we invented the submarine and rotating gun turret. The concrete tunnel tubes were built on dry land and barged into position. They were then flooded and sunk into position and tons of sand and BFRs (Big F$%%ng Rocks) were placed on top creating the artificial islands. The water was then pumped out and the road way attached. Then in true Southern style, we built a fishing pier, restaurant and gift shop on the Thimble Shoal island so all the Northerners can buy cigarettes and fireworks.
I don’t plan on doing any tunnels (not yet anyway), I just stole the support idea. A good deal of the span will be a viaduct, I’ll post more photos later about how it’s all going to work together. The steel bridge is just for that portion, viaduct the grades leading to it, and the rest will be elevated about 4-6" on wood roadbed. By attaching it to the risers with a bolt, I hope to be able to easily make changes and effect repairs without a lot of work.
It’s a bold experiment, but one I believe will pay off.