Large Scale Central

Different approach to tunnel building.

Track and Trestles
#1

I’m redesigning a section of the RR and plan to put in a tunnel. In other sections of the layout I have used cement block and 12x12 flue liner. I really like the flue liner because it can be installed and ready to go very easily the trouble is I can’t seem to find it anymore.

The alternative to flue liner is to make the tunnel from concrete 4x8x16 blocks and then buy large patio blocks for the roof and extra concrete for the floor of the tunnel. The blocks are $1.25 per and the large flat patio ones are at least $5 per so a long tunnel can add up in cost.

I had a brainstorm the other day. What if I placed one layer of the 4x8x16 blocks then dropped a sona tube in between the blocks then cemented over the top of the tube forming something resembling a Quansa hut. The track could then be affixed to a PT 2x4 and fed through the tunnel. a 5’ length of tube is $9.

Eventually the cardboard would rot out but that would be OK since the track isn’t sitting on it.

3 pieces of flue liner 12x12x2 is $75 if I can find it but it is quick with very little mess.

blocks and cement is approx. $50 and more messy work.

block, tube and cement approx. $40 and less messy work.

Has anyone done this?

#2

Todd Oh Todd

If you cut the sona tube in half and prop it up with bricks… when it cures , remove the bricks and reuse the tube!

coat the tube with a releasing agent… used motor oil.

#3

Quansa hut?

https://en.wikipedia.org/wiki/Quonset_hut

#4

Don’t forget 12"black plastic drain pipe.

#5

Good tip Sean.

Yes Joe a Quonset Hut You knew what I meant. I think a Quansa hut is actually where black guys celebrate that African Holiday?

I thought about the 12" drain pipe but who sells it and how much per foot? A piece of that could solve all this messing around with concrete.

#6

Todd Haskins said:

Good tip Sean.

Yes Joe a Quonset Hut You knew what I meant. I think a Quansa hut is actually where black guys celebrate that African Holiday?

I thought about the 12" drain pipe but who sells it and how much per foot? A piece of that could solve all this messing around with concrete.

I thought they did those celebrations in Australian airplanes. (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

Side of the road/pile of junk/abandoned for years behind some fence/construction site for 0.00 per foot? I got mine (5-foot piece of 10" plastic pipe) from some fenced storage area, with the owner’s blessing.

#7

My approach to tunnel building that i felt would hold up for several years and that would stay in a fixed level postion was a little overkill but they have given me 5 years so far maintence free playtime . i have installed 3 , two 12’ and an 8’ . i started out setting 3 treated 4x4 posts , installed 2x10 side beams , then framed up tunnel out of 2x12’s . in the first one i built i screwed track in , but the the other two i placed 1/4" alum. flat stock on each side of track so track would be removable if needed to . This may sound like overkill , but the mountains are but 7-8’ tall and i was worried about the down pressure and settling of the fresh dirt .

#8

If you can find “drops” of the corrugated black plastic pipe for free it’s a good deal. The stuff I used was 18"

BUT - If you want to buy it the shortest I found was 20 foot lengths at over $300.

I like the flue liner idea. I was going to use that to get under my front concrete steps. You should be able to still find it at any good masonry supply yard.

#9

Todd Haskins said:

Good tip Sean.

Yes Joe a Quonset Hut You knew what I meant. I think a Quansa hut is actually where black guys celebrate that African Holiday?

I thought about the 12" drain pipe but who sells it and how much per foot? A piece of that could solve all this messing around with concrete.

that would be a Kwanzaa hut

#10

Another thought is water or sewer pipe from your local municipal water company or city. I work for a public water utility and we have all sorts of pipe laying around. Now wax impregnated cardboard sonotube will last a very long time. I would seal the cut ends but that stuff doesn’t go away very fast.

#11

This is what I used. 12"X8"X12". My K-36 goes through with room to spare.

#12

I found a section of aluminum serated ditch 12 inch pipe and used it.

You can drive a car over this after it is in place with dirt packed around it.

Been in place for over 12 years now.

#13

Todd I have some 12" black Pipe!

Road trip and I’ll give all you need!

It’s time you got of that cape!

#14

On the SJR&P we have two types of tunnel construction. For tunnels longer then 5 ft we use pressure lumber for the sides and tops.

For shorter tunnels we use rock sides and tops. This is done by digging out the tunnel. Installing rock sides. Filling the tunnel. placing rocks over the curved top of the tunnel and then poring cement over the top. Once cured we dig out the tunnel.

Photo of pressure treated sides below.

Stan

3rd tier of rocks completed

#15

You guys build some stout tunnels. I am glad this thread came up because I wouldn’t even have thought to make them this sturdy. But I can understand why and will make mine in similar fashion. I can see the advantages and no disadvantage especially when I have heavy walled pipe free at my disposal.

#16

I went with the “pour your own” method. Sturdy enough to survive a nuclear blast. It was a fun project actually.

#17

Mike, those are just too damn perfect!

(clearly nicely done!).

Greg

#18

Perfect timing for my own tunnel project. I had planned on 8" wide by 11.5-12" tall and most seem to agree that is plenty of clearance. I run mostly 1:29 stuff so it works for me. I’m using block wall cap blocks set 4" below grade on end on each side of the track. Then, using more block to create a roof before covering with dirt. To support the two I’m drilling through the top into the sides and using 1/4 fiberglass rods to anchor it together. Lightweight but should be plenty strong where it is going. Because its going to be over 6 feet long the middle of the tunnel will have a landscaping box with a removable lid for those inevitable disasters. Bill

#19

Well you guys have some great ideas and have built some quite substantial tunnels. Given some of the ghastly critters you have over there I must say I admire your fortitude. I have two ‘tunnels’. The longer, 8ft., is in fact a two track, five car*, train storage. It has an access top. The other a dead end will house two cars*.

  • cars are 40ft. Aristo or slightly shorter Bachmann 1:22.5
#20

Guys, one thing about cement tunnels. Make sure they are on a solid base. I made a short tunnel with cinder blocks and a cap of a large paver. I even cast the portals so it looked like an official tunnel. Over the years it sank. I had to raise it up every couple of years or so, so that my Shay could pass through it. The last time I tried raising it up, the paver broke, and so did the south portal. I then dug it out and carted it off to the back of my lot.