Tunnel Construction

[tatorsalad]

Does anyone have some easy ways to make a tunnel.  The tunnel will be located on a corner of may layout and it will be N scale.

 

[ARTHILL]

The easiest is to just carve it in styrofoam. I have used WS tunnel forms, poured with Plaster of Paris. They work, but foam is easiest. Just stack the foam to make the mountain you want. Then carve the tunnel just like the prototype. For a blasted tunnel, just tear it out. For a  formed and lined tunnel, a hot wire works, or line the tunnel when done with patching plaster.

[rbakerphoto]

I used 1/4 inch foam sheets to line the side of my N scale tunnel which I then coat the sides with sculpt a mold plaster. I leave it fairly rough. Make sure you have clearance between the sides of the tunnel and your trains as they go through. Either color the plaster when you mix it or paint it after it dries. ( or both) I painted mine with Badgers brown and sepia paint. Then a coat of black high on the walls and roof. I then take a toilet paper roll or paper towel roll, cut it in half and line the inside with plastic wrap. Use the sculpt a mold on the plastic, forming the roof of the tunnel, let dry, and paint. I done this with the tunnels on my layout and am extremely pleased with the results. When it is done it actually looks like a tunnel that you blasted out of solid rock. Have fun and experiment.

[tgindy]

Tunnel Caveat:

Derailments can and do occur in tunnels.  Plan for reachable access if the need arises.

[BigRusty]

WRONG!

Derailments only occur on poorly laid track. A rerailer can be placed before the portal if you don't know how to lay good track.

Better yet, isolate the areas where derailments occur and FIX THEM! If it is caused by a defective car, FIX IT!

Just take it one at a time, and soon you will never have ANY derailments again.

[selector]

I think I can see both points of view here, and agree....how wishy-washy is that!

I have had exactly one derailment in the long tunnel that runs behind my yard and station that I built to keep trains from goofily passing behind in full sight.  So, I understood at the outset that if there was one section of track that I would not want to have to reach into, it was that one.  It is tucked up enough that getting to is is quite possible, but not very easy. I spent a lot of time on this 8' section and made sure it was flat, that the cork roadbed was firmly held into position, and that it was straight.  Finally, I made darned sure the two joins were foolproof in terms of derailments.  I nailed each of them at the closest ties to help the joiners, even if it meant drilling a tiny hole through the last tie that had the working spike heads.

That much was a no-brainer.  Yet, I still have had one instance where I had to pull out all the storage bins, and get on my knees to scurry up to the wall, and then reach way up, all contorted like, to try to fish out the one derailed car.

So, it happens.

I don't trust the rerailers.  They're not bad for cheap insurance, but they're not terribly reliable I find.  Too many misses.

That is how it's been for me.

[ham99]

All four of my tunnels are lift-off.  I make the tunnel form out of blue foam, then set it in place with a piece of Saran wrap under it.  Next comes the coat of Sculptamold, rocks, trees, and whatever else is needed for scenic effect.  When it is dry, I lift it off and remove the Saran wrap and the tunnel is a fit with the rest of the scene.

[dand200]

I am with Ham, however you make your tunnel, the extra work to make it accessable is worth it.  I stacked foam board insulation, carved it then added scenery, but I never glued the top 2 layers.  My tunnel is in a corner so the top scenery piece snuggles right into the hardboard facia.  I think the only extra effort required was to work the scenery on the lift-off section so it blended when it was in place.  Any tunnel section with a lift-out isn't something that will be frequently accessed so durability isn't as important as blending the seam.  There are plenty of ways to disguise it too; trees, fencing, hedgerows, rock out-croppings, etc.  The idea of perfect track work is great but so is the thought of running your trains without ever having to worry about recovery in case of a deraiment.  Good luck.

Dan

[bogp40]

If you have an open framed layout and the mountain is large enough, tunnel access can be made from undernieth or from a side access. If you don't have this luxury, removable sections as mentioned is a must.

The double track is fully accessible under this large hillside.

This cut/ tunnel is almost 12' long

Varying style of benchwork construction and overall plan would best determine the type of construction for your tunnel. "L" girder/ open frame can be cardboard lattice(as shown),wire screening, with hydrocal paper towel, cheescloth, plaster cloth or plaster or ground goop applied directly.

Other solid decked (plywood or foam), I would reccomend the method used by Arthill and many others of building up foam layers until you can cap with the removable top portion. Removable sections are much easier done with foam, rather than with the more permanant style as previously mentioned.

[HHPATH56]

I realize that this is in HO scale and it is not a corner tunnel, but it was a mountain of necessity, which required four turnouts within the tunnel. This meant that I had to have some way of access to the six tracks within the tunnel. I built this mountain wth arches of 3/4" plywood, so that I could make framed access ports on the side of the mountain. as can be seen in the incomplete mountain, which includes a mainline, a partially interior automobile tunel to the ski and skating resort on top, a mine with 3 tracks and a harbor crane serviced by two tracks.      I applied window screening and covered it with Hydrocal Sculpmold plaster. Hydrocal is extremely hard durable plaster, that stands up to fairly rough handling without cracking.    Bob Hahn

[Tjsingle]

Foam, hot glue, and the woodland scenics "mold a scene" plaster. the plaster molds like clay.

[MisterBeasley]

Even if you never have a derailment inside your tunnel, you will still have to clean the tracks occasionally.  I've got a CMX Clean Machine for that purpose, but I would still advise provide easy access to the tracks inside the tunnel.

I've got "almost perfect" trackwork right now.  Still, I get the occasional derailment, mostly from operator error (forgetting to set a turnout correctly.)  Remember that in that case, the train probably isn't going to stop right away, but may continue down the track a few feet before it either shorts out or gets noticed.  If that few feet takes it into a tunnel, you've got a problem.

There is no reason to assume Murphy will not be around your layout, too.  Plan for access.

[TomDiehl]

Tunnel Caveat:

Derailments can and do occur in tunnels.  Plan for reachable access if the need arises.

You mean "when the need arises."

Obviously Murphy's Law isn't enforced on Big Rusty's layout.

[Anonymous]

Bob

That rock wall, is that cast out of molds or are they rubber molds. I really like the look and need a wall like yours. It looks great.

[BigRusty]

"Obviously Murphy's Law isn't enforced on Big Rusty's layout."

Murphy has nothing to do with it. If you debug the track and the cars you will not have derailments. Derailments do not just "happen", they are caused, by bad track and defective rolling stock.

I operated two very large basement sized layouts from 1958 to 1984, and once debugged, never had any derailments.

Derailments aren't caused by Murphy. they are caused by you, the builder. No matter how hard you may try, you are not always going to lay perfect track or have perfectly operating rolling stock. But rather than tolerate derailments, determine the cause and FIX IT.

If you have a car that continuously derails, send it to the RIP track, and don't use it until you repair it. If you have a place in the track where this is a problem, tear it out and do it over. DUH!

Believe me, model railroading is a lot more fun without needless derailments.

[bogp40]

Bob

That rock wall, is that cast out of molds or are they rubber molds. I really like the look and need a wall like yours. It looks great.

They are the Cripplebush rubber rocks. There was a MR article on rejuvinating your scenery, Oct, Nov '06 I believe.  http://www.cripplebush.net/santa-fe/santa-fe-category.htm

I was quite surprised how easy they are to work with. They are a bit pricey though.

[Anonymous]

I thought so that is why I asked, I have been looking at them but some of the pictures on the website don't really give you a good example of how they look, are yours the "Blocky Rock"?

Thank you for your response, yes they are pricey but looking at yours they are worth it.

[bogp40]

I thought so that is why I asked, I have been looking at them but some of the pictures on the website don't really give you a good example of how they look, are yours the "Blocky Rock"?

Thank you for your response, yes they are pricey but looking at yours they are worth it.

These are the Santa Fe Canyon 1 and 3. I needed an extremely large mold/casting for this huge cut. Installing individual castings and blending was way too much work and would not look as good. Trying to continue any uniformity and strata would be near impossible. Since it can be viewed from about 18", using these Cripplebush rocks was the solution.

The 2 large sections are actually designed to blend seamlessly together for added height or length. Some careful trimming and fitting is all it took. I did bond the majority w/ ceramic tile adhesive. to the plywood substrate. Edges and seams were fit and glued w/ hot glue.

http://www.cripplebush.net/pages/santafecanyon1detail1.htm

Since the rubber is so flexable, and visitors wouldn't be able to resist pushing on them, I filled the hollows of the back of the casting with expandable foam. They recommend foam shims too much bother for the size. Once dried and expanded I just cut away the excess.            http://www.cripplebush.net/working-with-rubber-rocks/shims-in-place.htm    

They come primed a dark gray. Dusted them with spray paint to base color and allowed washes to settle into the cracks. It still needs coloring and highlighting.

Actually I am picking up 4 of the Santa Fe 3 at the Springfeild, MA show for the other side of the cut.

Nice product but not cheap.

[Kenfolk]

Murphy has nothing to do with it. If you debug the track and the cars you will not have derailments. Derailments do not just "happen", they are caused, by bad track and defective rolling stock.

I had no derailment from bad track or poor quality cars. The contractor working with the jackhammer was on the other side of the wall, and the vibration shook the cars off the track--

Likewise when he was hammering on the opposite side of the wall, it was like an n-scale earthquake!

So I always provide an access into my tunnel, even though I know my trackwork and cars are good. 

(I work hard to prevent fire in my house, too, but I also keep a fire extinguisher, and make sure the smoke alarms work.)

Just my two cents. 

[ham99]

Many things other than track and equipment cause derailments.  Operator error can happen, especially if you allow someone else to operate your railroad.  And I still forget to throw a switch from time to time.  Visitors jarring the benchwork.  A door slammed.  Even cookie crumbs dropped on the tracks.  No one can completely banish derailments -- not even the prototypes.  And, of course, cleaning and maintenance must be done regularly, so access is a necessity.

[DeadheadGreg]

How much are those Cripplebush rubber rocks?  The place is only like an hour away from my house, so i'm wondering if driving out there would be worth it to save on shipping or something

[bogp40]

How much are those Cripplebush rubber rocks?  The place is only like an hour away from my house, so i'm wondering if driving out there would be worth it to save on shipping or something

I haven't checked out all the products, but the popular ones range from $30-$70.

For actual costs and a style you want browse around their site.

   I just add to cart to show price.  http://www.cripplebush.net/index.htm

[R. T. POTEET]

"Obviously Murphy's Law isn't enforced on Big Rusty's layout.". . . . . . . . . . Murphy has nothing to do with it. . . . . . . . . . Derailments aren't caused by Murphy . . . . . . . . . .

I'll bet you that you don't believe in Santa Claus nor the Tooth Fairy either!

I do not like tunnels preferring to break/hide the monotony of my ovals with other scenery mechanisms i.e. structures, foilage, rock cuts, etc. I have, however, incorporated a few on my layouts over the years, all of them short. My preliminary designing for my (hopefully) soon-to-be-built layout is going to necessitate at least two short ones.

I don't know about Murphy but I do know about gremlins which suddenly leap onto your layout from who-knows-where-they-hide. They are enticed from their hiding place(s) by the presence of visitors. Despite meticulous trackwork trains can still come to griefs for unexplained - read: gremlins - reasons. I don't care how carefully I adjust my switches I still find an occasional picking-the-points an occasional - read: gremlins - occurrence. Admittedly most of my derailments have been caused by faulty/defective equipment and one of those defects - a dislodged screw - caused a derailment right at the entrance to one of those rare tunnels; my train remained intact and upright but even with my 0-5-0 switcher it was havoc trying to unsnarl. On another occasion - shades of SDP40F - I had the rear truck on a three-unit brace of old 1980-era Atlas RS3s keep derailing on one particular curve. It didn't matter which loke was trailing and it didn't matter which direction it was pointing, it just kept derailing at near the same location. Then, one day, those pesky gremlins returned to their hiding places and I stopped having troubles. You explain it!!!!!

. . . . . . . . . . model railroading is a lot more fun without needless derailments . . . . . . . . . .

What, pray tell, is a needed derailment?

[mononguy63]

I have hardshell-type scenery construction. For my removable tunnels, I just shaped some aluminum foil, spray painted the inside black, and set it in place. Gives a reasonable cut/blasted stone look. Not highly detailed, but, hey, who closely examines the insides of tunnels?

[twhite]

I've got 5 tunnels on my Yuba River Sub, 3 of which are accessable from the backside, and 2 of which are accessable by removing the portals (which are held in place by scenery, not permanently fitted).  The inside tunnel linings are only about 4-6 inches long, just long enough to fool the eye into thinking the tunnel is fully lined, so when I've had a derailment (and I've only had one or two), it's easy to remove the portal and lining in one piece and reach in and collect the errant rolling stock. 

Tom

[Autobus Prime]

Does anyone have some easy ways to make a tunnel.  The tunnel will be located on a corner of may layout and it will be N scale.

 

ts:



Plop!
http://www.internettrains.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=IT&Product_Code=MDP-4371&Category_Code=NSCSTRTUNMDP&Featured=

Personally, I don't like the foam-stack method. I think it works better if the whole table is sculpted foam, but when I tried it on a solid top, I got something that looked like a lump of foam stuck to a table. Might as well get that Model Power tunnel. I did have good luck once with a foam mountain covered in plaster, but once the time has been spent to shape the foam, one might as well save money and make a frame.

Usually I have built up a frame of scrap wood and cardboard, then draped screen wire over it and added plaster. My only scenery at this moment is a pair of small hills of kraft paper draped over a cardboard framework and stiffened with brushed glue. I think I'm going to have to have a geologic event, though, because our little boy has been tunnel-mad for the last week or so, after riding the zoo train...tun-nel tun-nel tun-nel...

[Phoebe Vet]

I suppose this might be a good time to tell about the time my 4 year old granddaughter brought Thomas the Tank Engine some flowers.  I don't know exactly when, or where she put them on the train, but my 4-6-2 K-4 Pacific found those dandilion stems in the tunnel.

Fortunately for all concerned, my tunnels are all open from the back.  I can reach every inch of my track.

[Bud M]

Hi;

Here's what I did to make a tunnel. For any derailment I can get to the stock from underneath the layout.

http://www.grizart.com/images/before.jpg

http://www.grizart.com/images/after.jpg

Hope the photos help a little.

Bud M.

 

 

 

 

 

 

Does anyone have some easy ways to make a tunnel.  The tunnel will be located on a corner of may layout and it will be N scale.

 

[West Penn]

Make your base which will not move but don't make the edge straight.  Place a plastic sheet (a garbage bag works well) over the area.  Then build the removeable portion.  I used plaster shell and worked up the underside and then the upper portion.  Once the plaster is dry pull it appart and remove the plastic.  Check the fit and fix any irregular looking areas.  Put the plastic back in when adding scenery details and remove once dry.  If you can see the joint hot glue bushes here and there to hide it but glue to just the lower or upper part.  I made the inside of the removeable portion out of foam and made sure it sat lower than the scenery edge so it would sit level and not break edges off when I removed it and sat it to the side.

[HarryHotspur]

WRONG!

Derailments only occur on poorly laid track. A rerailer can be placed before the portal if you don't know how to lay good track.

Better yet, isolate the areas where derailments occur and FIX THEM! If it is caused by a defective car, FIX IT!

Just take it one at a time, and soon you will never have ANY derailments again.

Actually, the tunnel itself can cause derailments if not properly designed. For example, if the construction of the tunnel is such that the clearances for the train are very close to the tunnels walls, and if the tunnel is not ventilated properly, and if the track is not perfectly centered in the tunnel, then air pressure will build up more on one side of the train than the other. This results in an unbalanced Bernoulli effect and instant derailment. Streamlined trains such as F7s pulling streamlined passenger cars are especially vulnerable to this problem.

This problem can be greatly alleviated by adding adequate ventelation shafts to the tunnel.

- Harry