Tunnel Construction

[ttrigg]

I would like to start a thread discussing tunnels. What you made, How constructed, How well it works for you, and any problems encountered.

A couple of days ago Ian made the following comment about my tunnel:

"I admire you for having a right angle turn under a waterfall you have a lot of guts and talent.

Very shortly i am going to have a water feature put in my pool, which will see a spray of water spouting out of a wall into the pool, I already have a track running under where it will be but i am going to live dangerously and put an elevated track under there as well.

That also takes guts I don't know about talent though."

My "planning process" (I use the word "plan" very loosely) is what is making my tunnel the most successful section of my layout.

My tunnel does in fact make a 90 degree turn under the water fall. Two years ago I started the "planning phase" of my layout. I took over the concrete patio and "built my layout" in reduced form. I left out fifteen feet of straight sections on each side, figuring that straight sections when properly placed would not give a problem. I concentrated on the curves and switches (turnouts/points). Got some "kids sidewalk chalk" and drew in the pond and it's component parts.

Getting the mock up doing what I wanted, looking at "traffic flow patterns" "stations" etc. Took three months. After determining that I would have a radius of 5 ft 4 in I started planning on the tunnel concept. I "dry stacked" cinder blocks to form the "tunnel", testing several different configurations. All the while keeping it to such a size that I could reach in from the ends to rescue any "derailments". That took me another 3 months. Next I got a piece of "marine plywood" and cut out the "floor" of my tunnel. Several coats of enamel paint later, I went to my local "airplane model" store got a bunch of "wing fabric and airplane dope" (the paint used with model airplanes that "shrink fits" the cloth very tightly.) Wrapped the "tunnel floor piece" with three layers. That piece of wood is so well preserved I think it will last forever.

Moving to the dirt, I built the tunnel walls (the cinder block) and tried everything out to full size. The tunnel has a concrete floor with drains, the track is attached to the wood with split rail clamps just outside the portals. Again I made sure that everything was going to work the way I wanted it before building the "tunnel ceiling." Once satisfied, I got a couple of high school lads to dig the hole for the pond then put the "roof" on the tunnel.

For the "roof" of the tunnel I cut slots in the cinder block to place half inch re-bar ever three inches along the blocks. Once the cement dried, I put in a layer of "cinder block caps" three layers of tar paper (roofing felt). Another layer of "cinder block caps" and a layer of the rubber pond liner. The "waterfall" resivoir sits on top of that. Between the roofing felt and rubber liner, the tunnel will stay dry. After putting the stones and rocks in the pond I started building my "rock mountain."

The tunnel has been in place for just over a year now, and the only derailments have been caused by collisions with the dogs. Or collisions with their droppings, which has been a few. I've since built my self a "track sweeper" attachment to put on a flat car and pu***hrough a tunnel. (take a bottle brush, small 9 volt motor, 9 volt battery, rubber bands, and slice and fold a coffee can, Presto Chango - instant track sweeper.) (I noticed someone is now selling exactly that on e-bay. His looks a bit better than mine, but doubt it works any better.)

Other than problems caused by dogs, the tunnel is the ONLY part of the layout that has not caused a problem of any sort. Now when I get ready to run trains, I count dogs, then run the sweeper around the track. The sweeper does a great job of cleaning debris off the track AND out of the switches.

If you want pictures of my mountain go out to my "newspaper" listed below.

Now I would like to hear your stories, about the successful and the not so successful, especially what you did to overcome problems. If every one who has a tunnel will post here I do believe we can develop our own "How To Build A Tunnel Book" right here.

Highlighted only for emphasis only, not shouting.

[Buckeye Riveter]

I don't have a tunnel, but some of the best tunnels liners I have seen use a plastic product called ADS pipe. It is corrugated on the outside and smooth inside. Most people seem to use 12" or 15" pipe. It is very sturdy since it is also used beneath highways.

[Karl Reichenbach]

For my tunnel I used 13"x13" chimney flue liners. The track is laid the same as the rest of the railway with nothing special. I cut one side out of the flue liner and set it in place over the track. I covered the top of the flue liners with 30mil rubber flashing held with flashing adhesive. I attached wood tunnel portals to the end, and backfilled with stone and dirt.

I have not had any problems in the tunnel in the two years that it has existed.

Karl

[Anonymous]

Yes gentlemen this is a worthwhile subject and matybe even the coffee shop boys might contribute.

Tom your thing sounds terrific and well planned and executed I don't think I would have the patience to do all that and Doreen certainly wouldn't; we do all our stuff together

The products the other guys mentioned sound really good but I don't know if i can get them here in the tropics. However I still have the problem of suiting my tunnel portals which are hard to get in concrete (cement) which is the theme of my layout!

My tunnel is now working perfectly with only a 225 mm or 9 " pipe and the onlyreason it acted up was through me not doing it properly to start with.

Rgds Ian.

[ttrigg]

Ian

Bonnie and I do the GRR together as well. She participated in the testing. In fact she was a very sharp critic of what I had planned. She was the one demanding all the perfection. If it had been totally up to me, I would have thrown something together fast and spent the next few years debugging everything, just like I did in HO and N. It is by following her instructions that the "debugging" was done before the dirt was moved.

[RhB_HJ]

Contrary to the prototype Rhaetian railway, I have planned for only short tunnels.
Having studied Murphy's Law and its derivatives, the tunnels will be no longer than 6 ft (that's the one where the slabs can be removed), everything else is almost straight and short.

I get the chance to operate on a very large HO layout ( 120 engines, 2000 cars) with plenty of tunnels. If things go wrong chances are it will be in a tunnel (simply because one can't see what's happening!) and most likely in a tunnel where the layout owner is not pleased because it is very inaccessible. Nough said!
BTW while short tunnels make for more visual interest, long tunnels are just hiding trains.
But I'm waiting with bated breath for the first Large Scale subway (underground, metro) system.

Now as mentioned earlier if I were to build a long tunnel I would:

a) get a round pipe to fit a board that is 1.3 times wider than the max. clearance. The board will pretty well self-level in a round pipe.

b) mount the track on the board, as an option one could mount the rail directly to the board. This would provide for easier clearing if and when required. Install jumpers at every rail joint!

c) install the board, connect the track ends with rail clamps.

As mentioned in the other thread:
no ballast, more or less self-levelling, enough clearance under the track board for drainage. Board can be removed as one unit if required (depending on local conditions).
Installing (removable) portals would be just as easy as under other conditions.

[John Busby]

Hi trigg
My tunnel was not planned.
I was forced to put it in by a plant that really liked where it was put and grew larger than the lable said it should and
in Kalgoorlie when that happens you don't mess with it geting a nice garden here is not the easiest thing to do.
The tunnel liner is 3' of large diameter poly pipe the mines use for water supply .
It was slit for the track and later strapped with alluminium straps to prevent the gap for the track closing with the heat
Later still the track was removed and a section of track with no joints in it
was placed in the tunnel to aleaviate yet another problem derailments in the middle caused by the track joint sinking..
The track just floats in ballast through the tunnel a nessecity on my line which has to be periodicaly checked.
The hill is the aforementioned plant a golden diosma
Just have make or buy some tunnel mouths and retaining wall now to complete the tunnel.
Not to mention the occasional trim for the plant to slowly make it hill shaped
regards John

[Anonymous]

Hey John;

How did you tunnel under the diosma?

My effort is much simpler and as I said if i had of done the job properly in the first place it would have been no trouble at all.

I used club rail which comes in 3.6 m lengths, but it does have a single joint inside it. I Used LGB joiners and soldering them and I can tell you no trouble at all. My tunnel is 1.88 m long and track is lafd on quarry fines ballast as straight as a die. I lined it with a 225 mm or 9" storm water pipe with walls abouy 4 mm thick. This sits directly on the ballast, an equal distance on either side of the sleepers (ties). I got what looks like six tent pegs and drove them into the ground positioning the pipe and holding it in place irrespecrtive of pressures from settling earth.

I then built 2 Jigstones tunnel portals out of concrete ( cement) blocks which we cast using jifgstone moulds.. For your information the portals are made using a variation of the same set used for making all the spans for my viaduct.

Really i am now confident i have done a good job and it will work ok for years.

Rgds ian

[John Busby]

Hi iandor
That was easy I built the track then planted the Diosma[:D]
It obviosly liked where i put it as it has grown very well.
Secatures where the tunneling tool of choice[:D]
regards John

[Anonymous]

Is your diosma an Australian golden variety mate?

Ian

[ttrigg]

diosma?

Can some body post a photo, have no idea what kind of plant you are talking about.

[John Busby]

Hi iandor
Yes.
The moral of the story don't believe whats written on the plant lable.
regards John

[Anonymous]

Tom mate;

I havent got one myself if I get one i will send it to you, john may be able to send you a photo of his.

As Australia was part of the old Gwandanaland just about all our flora and fauna are unique. for instance just about all our trees are eucalypts and don't lose their leaves and all our animals except three are Marsupials (carry their young in a pouch).

If you had only ever lived In Australia you would never know how different this country is but I have traveled now to all continents except Africa, South America and Antarctica and i appreciate how different everything is!

Rgs Ian

[ttrigg]

Ian;

Back in '68 I spent five wonderfull days in Sidney. Took a "day trip" through the country side, yes I know I didn't get to see much, but what I did see was beautiful. (R&R from 'Nam)

[John Busby]

Hi ttrigg
http://www.hellohello.com.au/landscape/landscape.html
http://www.fernview.com.au/varieties/coleonema_pulchrum_aurea.php
the above links will show you what the plant looks like
SWMBO thinks it looks nice with the golden yellow leaves and tiny pink flowers.
I can only prune 20% at a time aparrently but that will have to wait.
It might just show on the picture of the simple signal I made
which is somewhere on the forums as the signal is close by the tunnel.
thats the best I can do at the moment I never seem to be home when the sun is in the right place for photography and I am not that good at it
regards John

[Anonymous]

Yes Tom

Do you remember where you went; i lived in Sydney for 60 years and in my opinion it is the top city in the world. And this a considerd opinion as i have visited most of the recognised top cities and it will leave Paris for dead; which is my second favourite city.

Sydney Harbour is world famous yet it isn't Sydney's best waterway, The Pittwater, Hawkesbury system will leave it for dead both for beauty and as a boating veneue.

I don,t know if any ones knows it but what makes Sydney what it is. it has four seaports and seven rivers running through it. And sea coast areas can be formed by two methods, erosion which most are and Rhia or the result of volcanic eruptions millions of years ago and when the water level rose after the last ice age presto you had some incredible scenery.

I don't know if you know about the Whitsundays Islands it was formed the same way only it was a range of mountains that run down hill into the lowlands. again the lowlands got covered in ocean and again thousnadsa of beautiful green tropical islands, without a palm tree in sight. They were also part of the old Gwandanaland and it didn't have any palm trees or deciduous plants.

You might guess you are onto one of my favourite subjects.


rgds ian