# Need help with tunnel.



## iowafarmboy1960 (Jan 6, 2008)

I've attached a pic to show the location of my first tunnel. I know there are several ways to build tunnels, but I could use some suggestions. The track in the ditch is close to level. I was thinking about chimney flue, but don't no where to find it in Minneapolis, MN.


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## Gary Armitstead (Jan 2, 2008)

How long is the tunnel? You will probably need access to the interior for the inevitable derailment. The "S" curve could be "dicey". Would roots from the adjoining tree be a problem down the line? Looks like a good location.


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## iowafarmboy1960 (Jan 6, 2008)

The piece of wood laying across the ditch is the end of the tunnel. The tunnel is 2 - 12" straight pieces, 1 at each end of the tunnel, and 3 - 6.5 diameter curves. I was thinking about pouring concrete, until I attended 2 garden railroad open houses yesterday and it was suggested to using chimney tile. The upper track will also be a tunnel at the same point.


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## cape cod Todd (Jan 3, 2008)

Hello 
Recently I put in 6' straight tunnel using 3 pieces of 12x12 flue liner. my local hardware\lumber store had them for about 18$ per 2 foot piece. I have another tunnel that I made 2 years ago that incorporated a curve. I didn't have alot of money then (as if I do now) and had to use what was on hand so I used plywood that I cut easily to look like a big candy cane, painted it up, wrapped it in plastic and placed it on a bed of gravel so it wouldn't be sitting and prematurely rotting in a puddle of water every time it rains. It only has a couple of inches of dirt on top of it and large rocks on one side. I know I will eventually have to replace it when it does rot out but for now it was an easy way to work around a curve. I did use concrete to fashion tunnel portals. 
Do put in an access hatch you will need it if you can't reach the middle of the tunnel with your hand. 
Will this tunnel be in a spot where it will be walked on? If so build it tough. 
How will you seal the sides around the curve if you use flue liner? Concrete? 
Todd


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## altterrain (Jan 2, 2008)

Using flue tile will require some fancy cutting for the curves. I used thin concrete block (4"x8"x16") for mine. They were set on end trenched and mortared in with mortared blocks on top. More mortar was used for the tunnel floor. I used scraps of pond liner on top to keep them dry but a few layer of heavy plastic would work too. The curves will require a wider tunnel but you could use 2'x2' concrete pavers though they still require some cutting. They can be cut with a diamond blade on an angle grinder with a trickle of water to keep the dust down and blade cool. Much easier and cheaper than working with flue tile. 










-Brian


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## snowshoe (Jan 2, 2008)

I just used some cinder blocks and stacked them to the height I wanted. Then I had some nice walkway pavers that I used for a roof. I sealed where the pavers joined so no water would leak in. Then I placed a heavy duty tarp on top for more protection. I dug large hole in the tunnel and filled with stone. This helps with drainage, gives a place for the water to go. 








I took the pavers on the bottom out and used the stone.


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## engine 72 (Jan 6, 2008)

I made a box out of 12" x 2" x 10' treated wood and then added a hindge on to access it if need be. Really simple and it works great. 

Todd


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## iowafarmboy1960 (Jan 6, 2008)

Well, I just went to Menards and bought a 15' black, flexible, plastic culvert. I'm taking it back in the morning, because I couldn't get it to bend to the curve of the track. It looks like I'm going to be pouring concrete.


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## cape cod Todd (Jan 3, 2008)

I like that idea of using concrete block and pavers it makes for a very strong tunnel. 
Iowa don't forget the access hole for the inevitable derailment and try to keep the use of rail joiners to a minimum by using clamps or soldering or jumpers because we all know that electrical issues and shorts will happen in the worst places. I have a spot where my mainline goes under an addition on the house through about a 24" tall crawl space, it seemed like a good idea at the time, but sure enough I was crawling in there today to give the engine a push over a bad spot. I gotta get more clamps.


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## wigginsn (Jan 9, 2008)

Here's a link to a way over the top tunnel build I've just finished. 

http://www.mylargescale.com/Community/Forums/tabid/56/forumid/9/postid/33519/view/topic/Default.aspx 

I poured the whole thing in concrete but I would have used cinderblocks or pavers for the walls if I had them on hand. More of a cheapskate decision as I had everything but the steel laying around home to do it all in concrete. 

Make sure you let us know what you end up doing. 

Cheers 
Neil


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## iowafarmboy1960 (Jan 6, 2008)

Neil, 

I have another post on here detailing my progress on the garden railroad. It's titled "garden railroad finally started". I've just posted 2 new pics. I followed your example and went with concrete. There's going to be a upper pond with a stream over the 2 tunnels, dumping into the large pond. So, I'm going to have some dirt & rocks on top of the tunnels. 

Tom


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## Torby (Jan 2, 2008)

I think I'd make it a cut, rather than a tunnel.


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## Ward H (Jan 5, 2008)

Chimny flue liners work great for straight tunnels but as Brian said, would take some fancy cutting for a curve. Concrete block and pavers would work best. Poured concrete makes for a very permenant tunnel, too permenant for my taste. Never know when you might want to change to a larger curve or move things around a bit. 
Of all the ideas posted, Torby's sounds the best. A cut lined with rough stones and a stone bottom for drainage would look real good and give you a lot less trouble down the road.


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## Ward H (Jan 5, 2008)

Just checked out your other thread and saw why you wanted the tunnels. Go for it. Nice plan so it will be worth the work. Think about using 5' flex rail bent to the curve instead of sectional. That will give you less track connections to worry about in the tunnel.


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## Caseyjones012 (Jul 29, 2008)

Because of a nagging concern that even PT wood rotting over time, I built a 14’ long curved tunnel (10’ rad) using PVC lumber “welded” with PVC cement that sits on a bed of concrete pavers. I installed two access hatches at third points. 

Were I to do it over, I’d like to try the flue tile method. I think they could be cut to the appropriate angles with a masonry saw. 

Geoff 

Geoffrey D. Cullison 
President and Chief Operating Officer 
Sheldon JW Cullison 
Vice President, Chief Financial Officer, and Chief Botanical Officer 
The Arlington and Little Falls Railroad 
[email protected] 
Member of the Washington, Virginia and Maryland Garden Railroad Society


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## iowafarmboy1960 (Jan 6, 2008)

Ward, 

That's a good suggestion. I'll think about using flex track. 

Thanks, 
tom


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## John J (Dec 29, 2007)

I used these to make a curved tunnel 

























These allow you to make curves very easily. only draw back is they are only 8 inches hight. If you want 10 or 12 inch hight you need to pour a footing. 

I put hardi board on the top for a roof. ( The concrete board one uses for under tile in a bathroom.) I put rebar on top of that with 1.5 inch of concrete. 

I drove rebar into the ground through the void in the block. I then filled the void with concrete.


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## iowafarmboy1960 (Jan 6, 2008)

John, 

Did you put mortar in between the blocks or just set them together? Where can I find them? I've looked on the home depot, menards, and lowes web pages and can't find them. 

Tom


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## Webber (Sep 4, 2008)

If you're going to have water nearby or water falling from above you should especially take care of drainage inside the tunnel as suggested by another post AND reducing the amount of water intrusion from above. Consider using roofing tar or other sealant that is used on exterior of concrete foundations (when full sized houses are built) before back-filling with soil and stones. This sealant is frequently applied before a water-proof membrane and/or expanded poly-foam boards. (which you might wish to use for your application)


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## Richard Weatherby (Jan 3, 2008)

I have tried both the concrete block and the flue liner method. The curved tunnel did use flue liner but the pie shaped gaps were covered with cheap porcelain tile samples and covered with some pond liner or old shower cutain. 

The photos below show some of the three story tunnel done with concrete block and pavers mortared in-place. One tunnel is 16 feet long. The trap door in the middle is a hinged stamp mill which allows acess to all of the tunnels. 12 portals. The center portion contains the "Dew Yew Mine" and the "Eye Dew Mine," a dog bone track.


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