Hi guys,
I am in the process of expanding my layout and have plasn to add several tunnels. What is the best way to build a tunel? What are the best materials to use to close in the tunnel?
Thanks
Hi remember rule 1 do not make tunnel more than 2 arms lenth so that you can reach a loco if there is a problem. 2 tunnels can be made by bending strng wire tothe shape you want then cover shape with small mesh chichen wire. 3 Cover this with any thing that will hold the shape IE old bed sheets blankets. 4 To make a hard finish and to shape it talk to your local biulders merchant he will advise you on what to use, remember you do not want a lot of wieght it the construction Hope this helps[:)]
As usual i largely disagree with what has been said mainly about the two arms length stuff.
I can speak with some authority as i have 4 tunnels and they are all different, for different reasons. One is 1.9 m (6.3’) another is 200 mm (8") and the other is a double decker 2.8 m (9.3’) long and i have used 3 different construction methods which suited the situation at the time. The little one is two overlapping holes bored through a concrete (cement) wall. The double decker was a cutting betwen the pool pumphouse and the back fence, that we covered in and the other is most interesting in that i used a 220 mm (9") plastic storm water pipe and i cut a 150 mm (6") section out of one side over its entire length and that become the bottom through which the track passes.
The amount of trouble i have with 3 of them is not worth talking about and if anything gets stuck i send my big Mallet through and it will push just about anything out and in the rare occasion that doesn’t work, i use a bit of wood and push it out, even a mop used backwards will do. The other one the storm water one; i did have trouble with but it was my own fault as i didn’t do the job properly in the first place.
Rgds Ian
David
“What are the best” Man do I ever hate that question!!! What is best for me could very easily be the worst of all possible choices available to you!!!
Two Tone says to keep it light.
I’m going to tell you a way to make it VERY heavy and durable.
In my case, the tunnel had to travel under the waterfall box for my Koi pond. I used 8x8x16 cinder blocks, re-bar, concrete, 2x8x16 cinder block top caps, and about a thousand pounds of rocks and over a dozen bags of mortar, and about 20 boxes of different concrete color powders. To build the tunnel I laid down two rows of cinder blocks twelve inches apart on a concrete foundation. I dry stacked a second row of block using a half block at each end to get the normal staggered stack. The top row of block had 4 notches cut out of one side of each block. I bent re-bar into a “square U” shape large enough that it would reach from the bottom of one wall, span the gap to the other wall and down to the bottom of it. I then mixed concrete and filled the slots in the blocks, securing them via the re-bar. I then spanned the gap between the two “walls” with the cinder block caps, these sit directly on top of the re-bar. Since I needed to waterproof the tunnel, remember it goes under the water fall box, I then covered everything with several layers of roofing felt (tar paper), then a layer of pond liner membrane. On top of this I put the waterfall box along with the required PVC pipe. Then I covered everything with rocks held in place with mortar. As you can see I needed to go heav
I used 6"x12"x2" pre cast concrete bricks that you can get at Home Depot for around a dollar apiece . Stand them up on a compacted base and mortar them together next to each other . Then use them to form the roof . Then I covered the roof with a landscape fabric and covered it with dirt . Its easy to form around curves or straight sections .
Looks GREAT Mike would like to get the engine and the tunnel at a lower shot. You think smaller crushed creet would look ok or higher the effects? Just asking!? Paint it brick red then tint it to older mossy red? Sorry just got to excited about your train there, dang it looks great!
Those bricks come in many colors . I just used regular mortar mix . Heres a few photo’s I took today of the tunnel .
Mike;
In your photo:
It looks to me as if you went that extra step and put in some “timber framing” to “support” the walls of your tunnel. Looks good, I like it! If that is timber framing I see, did you put it in while building the tunnel or later?
I hate this Tom, but you and i agree once more, there is no best way. Different methods suit different people in different situations.
Do me a favour mate and say something i can disagree with!
On to Tunnel portals, I have a Jigstone kit and as my layout is European between the world wars; i have my tunnel portals made of concrete in a stone pattern, I willpost a photo if i can.
It is the arch span mould pattern modified so its really the same as my viaduct project but used differently.
Rgds Ian
No Tom , actually the bricks come that way . Those are score line groves if you want to break the brick to shorten it . That tunnel is about 5’ long and it was real inexpensive to build .
A few pictures of my tunnel portals in area 1 under construction a few years ago.
Ian
Sorry but that is area 3 not area 1 and it is now much more greened with a complete coverage of lawn over the tunnel roof.
You can aslo see my dreaded 4 % gradient with R2 curves under constrction.
Also note club rail 3.69 m in length which i bend myself and cut to size.
Hardly any joins and any shape and size i require.
Rgds Ian
Ian:
Is this the infamous 4% twisting turn you constantly state you wish you had never built?
Is that a paved pathway under the bridges? My wife would never let me get away with something like that. I’m getting enough verbal abuse from her over a little three inch transgression onto the very corner of the patio where the track turns away from the pond to head out to Vine Arbor.
Hey guys,
Thanks for your help and my deepest appologies on the wording of the question. You can tak emy word for it, I will NEVER make the mistake again[:)] I really liked the way Mike biult his tunnel with the cement blocks mortered together. That will be the BEST way for me.
Thanks again guys
David, what did you think of the portals, i know they are not American more European but i made them myself out of a Jigdstone moulding kit.
Tom yes this over a concrete path, as you know i don’t have a backyard as such and this is a courtyard out the back, which we allocated for my railway. I will post a few photos later showing what it looked like before i started, including an idea of tunnel construction. Also photos of the completed thing.
Tom it is not for me to gine marital advice but i had a wife that was hard to get on with and i got myself a new wife; 24 years ago now and it was the best thing i have ever done.
Rgds Ian
I also use concrete blocks for my tunnels, although I used Elmer’s urethane glue instead of mortar. One thing to bear in mind is that you want good solid ground under your tunnel walls to prevent settling, especially if you will have a sizeable mountain on top of it. Even then you may want to keep the height of your tunnel a little on the high side so that if it does settle over time, your tunnel won’t become too low for trains to pass through.
I like to apply textured, tinted cement to the inside of my tunnels, at least near the portals where it shows. This makes it look more like blasted, fractured stone.
I have pics of my tunnels and their construction on my website:
http://albums.photo.epson.com/j/AlbumIndex?u=3009006&a=32116967
While Ian isn’t particularly fond of the “two arms’ length” rule to tunnels, I’m here to tell you it’s a good rule of thumb. (Or would that be “arm?”) Actually, you can go two arms’ length plus a foot or two, because all you have to do is be able to reach in and grab the end of the derailed loco or car. Having had the “pleasure” of contorting my body to try to reach inside of one of dad’s longer tunnels on more than one occasion, I really don’t recommend it for anyone who’s–shall we be polite–less than nimble. Yeah, broom handles can work, but I prefer a less destructive method of retrieval.
If you must have a long tunnel, I’d advise against ballast of any kind, and secure the track to a firm subroadbed to keep it from shifting and twisting within the tunnel. You’d also be well advised to block the entrances when not in use to keep leaves and wildlife out. All too many times, I’ve seen furry and reptilian things scurrying out in advance of the trains.
Getting back to building materials, the cement blocks mentioned above are good. I used a similar technique, using 2’ x 2’ and 2’ x 3’ patio pavers for the tunnel on my old railroad. They’re set on end into the ground about 10", which keeps them from being pushed inward over time. The top is capped with additional pavers.
Later,
K
Well Kev mate, we will agree to disagree on this one. All the best.
Rgds Ian
Actually, Ian, there’s nothing to disagree about. Long tunnels are unavoidable on many railroads. I mentioned my dad’s railroad earlier–4 of his 5 tunnels violate the “rule of arm.” But in building tunnels or any track where the train is inaccessible, there’s an inherent risk. When designing your railroad, you need to take that risk into consideration. If you run collectible pieces, or are all thumbs when it comes to repairs, then keeping your tunnels accessible greatly diminishes your chances of irreparably damaging your prized rolling stock.
It’s like building a bridge over a pond. There’s an inherent danger of the train getting wet. You can take steps to mitigate the danger (guard rails, etc.) but the only way to completely avoid the danger is to not build the bridge over the pond. When you build a long tunnel, you can take steps to lessen the chance of a derailment, but you cannot completely eliminate it. So long as you’re comfortable with the consequences, then there’s no issue. If it were my $3,000 locomotive getting pushed out with a broom handle leaving a trail of detail parts and bent valve gear in the process, I’d be seriously rethinking the length of that tunnel.
Later,
K
Greetings,
As I have no tunnels on my layout, and at present have none envisaged, I found this a very interesting topic.
When I started my construction last year I noticed that many advised against tunnels - other then very short ones - for a few reasons i.e. Murphys Law derailments, animals settting up home, and the difficulty of stock retrieval when no longer agile.
I see Ians’ views and they obviously suit him and maybe he is prepared to risk some possible stock damage, but I go with Kevin regarding that point.
My No.1 son who lives locally to me was keen to construct a tunnel where the rail line crosses a pathway which leads on to a lawn. It seemed a good idea at the time but I realized that it meant steps to negociate, possibly in haste, and therefore a source of injury.
I haven’t discounted the idea of a tunnel entirely but feel that a very short tunnel (not much longer than a standard sized G scale boxcar) could be used as a scenic break and to me that would be permissable.
At least in this realm we have very few dangerous reptiles or insects to worry about. It is interesting that this facet of the possible problems did not arise - I am sure Ian and those in the U.S.A. could tell us if this is a problem to them and how they overcome it.