# Suggestions for tunnel



## mickey (Jan 28, 2009)

I am getting started on the area outside and need some input for the tunnel. I already know that I want to be able to get arm in from each end and no more just in case of derail, etc. It will be a 8 foot dia. curve track taking just a 90 degree turn. First, what do most people use for the tunnel? I thought about some sort of black flex irrigation pipe, but not sure if it comes in a suitable height. Do most of you free-form a cement or what? Suggestions and pics will be greatly appreciated as I want to learn form others mistakes. Thanks in advance.


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## Matt Z (Dec 2, 2009)

Hello 

You can't go wrong with plaster cloth. It's fairly cheap, it molds and dries well. It's easy to install scenery on as well, and you can always put more coats of hydro-cal or rock castings after it dries. Making a substructure out of cardboard, mesh, newspaper, or heavy construction styrofoam ( works great underneath. By doing this you won't need to worry about any piping for your trains to go through. 

You can pick up this plaster cloth at most hobby stores for about 10 or so bucks a roll... 
If you have a Micheal's or JoAnn nearby, they carry it there and they have an abundance of weekly coupons for 40 percent off a single item. 

Another option is to get a bucket of hydro-cal which is like plaster but dries much quicker and is more optimum for carving along with making rock castings. Mix it in a larger container or even a long tupperware. Get some EMS cling- your local fire station will probably be able to give you a handfull of that. If that doesn't work just head to a drug store and buy a box. this is basically you making your own plaster cloth. This will get you a lot further a long in the process spending a lot less money. 

Any other questions please let me know. I, along with many friends of mine have used this process over and over and it has never failed any of us. 

I'll see if I can round up some pictures for you. 


Matt


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## Totalwrecker (Feb 26, 2009)

On my tunnel I built a bench above as a viewing area. 
happen to have salvaged a pecky cedar ceiling so I used that. 
First I graded the roadbed, my track floats in ballast, no hold down screws as I have extreme temperature fluctuations and my rail expands and contracts during the year. I framed a channel 1 1 /2' wide for the track and made a solid wall for the inside curve, I wish now that I would have made another wall for the outside half... but because the bench would sit on a box, I merely used a strip of plywood, as a bender board to contain the ballast. My tunnel is 10' dia. 1/4 turn, so I added a top access hole and seem to need it every time there's a derailment or critters... because as I've added details outside, my inside reach as grown shorter! 

I used CementAll to make a painted desert look on the inner face of the tunnel exterior. I used stucco tints to precolor the cement as I laid it on wet dirt in thick color strips. I like CementAll as it doesn't shrink (very much if at all) and sticks to previous pours. Should be a national brand and I get it at Home Disapointment out here.... I've since covered that wall with mine tailings.... 

It's wise to have doors that seal the bore between runs as well to keep critters and weather out. 
There are threads (forum entries) that cover peoples various solutions, including irrigation flex tubing. I would shy away from that tubing tho', because it's hard to avoid bumping the wall while using the 0-5-0 big hook! lol 

Go through the forums, there's a ton of information and great ideas.... 

John


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## John J (Dec 29, 2007)

I used concrete block like this.
.









One problem is it is only 8 inches high. You want about 10 inches or more. So you have to add some smaller bircks 

The reason I used this is It allows you to make a tunnel with a curve 

For a top I used Handi Board 











This may seem like a lot of work but I then put big natural rocks all around.










Then there was the famous one piece pour which netted me a 480 pound tunnel ( this is where you learn from my mistake. 











I built a form but made the walls too thick. and the top too thick. There is a rebar cage in the concrete. It took 6 bags of 80 LBS each of concrete to fill the form 




















I then put large rocks like this all around it so there fore I had to make it strong





















YUou may not go a crazzy as I did but It may give you some ideas.


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## Randy Stone (Jan 2, 2008)

All great ideas above, but one thing not mention is drainage. Make sure the tunnel is not the low point in it's surrounding area. I would suggest giving the tunnel floor a slight slope to one end that will drain the best.


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## Steve Stockham (Jan 2, 2008)

I pretty much did what JJ did except I used those 15"x15" cement slabs. I buried the slabs into the ground about 4-5" so I had the necessary clearance but I used gravel inside the tunnel to allow for drainage. 










I caulked the seams and then filled in with dirt. Once I had a solid base I set the liner and began making the waterfall. I then set the stones in place and voila!


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## Richard Smith (Jan 2, 2008)

Rick Marty did a tremendously neat tunnel and posted it here awhile back. A search hopefully will bring it up or maybe he will see this and refer you to it. Very realistic!


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## Matt Z (Dec 2, 2009)

Mickey, hey sorry about that, for some reason I thought you were talking interior! MY BAD! If you evey decide to go inside there's an explanation of tunnels inside hahaha. It was definetely early when I was reading and writing this morning. 

Here is a shot of a tunnel that has what I believe to be 2x10 interiors. 

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Take care 

Matt


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## Randy Stone (Jan 2, 2008)

Posted By John J on 21 Feb 2010 10:27 AM 


Then there was the famous one piece pour which netted me a 480 pound tunnel ( this is where you learn from my mistake. 











I built a form but made the walls too thick. and the top too thick. There is a rebar cage in the concrete. It took 6 bags of 80 LBS each of concrete to fill the form 






So JJ, I see the hydraulic jack inside the tunnel. Were you trying to raise the roof?

If you lived in Kansas, you could use that tunnel as a tornado shelter.


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## aceinspp (Jan 2, 2008)

Seeing how I had to make a cut and reinforce the walls of the cut with cement I ended up making part of it as a tunnel about 4 ft in length. Worked quite well doing it that way. Later RJD


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## John J (Dec 29, 2007)

I had set the 480 LB tunnel on some one inch pipe to slide it slideways to get it where you see it now. The Jack was to lift the tunnel to get the pipes out.


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## hans911 (Jan 9, 2008)

All good ideas. However, I did my tunnels yet another way. 
First I built a rough wooden. Then covered it with chicken wire and covered that with burlap or old sheets drenched in concrete. Painted with white outdoor latex then added a numer of coats of wash with acrylic paints from Michaels and voila.....Tunnel. 









Rough Frame 









After concrete covering 









After painting


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## Torby (Jan 2, 2008)

The tunnel is the place where Madam Mallet crawls off to die when her battery runs dead and I haven't noticed.


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## Trainwreckfilms (Aug 19, 2009)

I too did the Cement Slabs. I can walk on the sucker... building cost was about $50 Been holding for 5 years now. Check my websites video and toward the end you will go through the tunnel


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## Richard Weatherby (Jan 3, 2008)

I am a strong advocate of the actually laying concrete blocks 2 high and then covering with 2 inch thick concrete pavers. I have been walking on it for years now. It is 3 stories (18 inch each).


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## jimtyp (Jan 2, 2008)

Dick, great looking tunnels! Do you put anything between the side concrete blocks to keep them from caving inward?


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## Richard Weatherby (Jan 3, 2008)

Jim, The back ones (dirt hillside) are 8 inch blocks that the cells are filled with cement and rocks. Loose gravel & drainage behind helps prevent pressure from earth expansion. The weight on top seems to prevent movement. I also waterproofed the back and covered it with a shower curtain & cheap insulation to prevent punctures. The Stamp Mill seen in the photo is hinged at the front and is the trap door to the center of the 16 foot tunnel. The tunnel protects the track and derailment has never been caused in the tunnel. I have driven a derail train in there. 

I also have used 18 x 13 inch clay flue liners for tunnels. I have placed pond liner over those similar to my cheap waterproofing. Sand can provide good drainage and protection of the waterproofing. 

I live on near the East Coast of US and we get plenty of rain and snow. The Mid Atlantic recent back to back 20 inch snows. It is all still burried.


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## mickey (Jan 28, 2009)

Thanks for all the input. Things have been brought up that I would not have thought about. Since mine will be in a 1/4 turn, I can see I will be best off doing a custom probably with cement blocks then sealing with hydrostatic cement. This will actually be going thru the corner of a retaining wall holding a garden bed, so I will have to make sure I seal it good. Thanks all.


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## Hamers (May 11, 2009)

Hi there,

I use a concrete block construction similar to others posted. I start with a 100mm foundation and build two courses blocks high, fill them and cap across them with 50mm capping blocks. Run some polythene over the top and cover with soil. 

Here are a couple of pics of one I completed recently length is approx 1.2m long.









I cast some concrete tunnel portals first.









Concrete blocks are in place and filled, portals are in place, because of the back fence line I opted to put a steel frame in to support the roof capping blocks.








Soil and rocks in place, with ballast needing to be completed.

This is the next tunnel under construction approx. 3m long, and will have access from behind The blocks still need to be filled and back piers to complete.










Cheers,

Andrew


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## mickey (Jan 28, 2009)

Are those tunnel entrances stone, foam or what? What are the inside and outside measurements and where did you get them? The look nice and would work for what I am planning.


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