how do I build a tunnel

[ontario mainline]

like the title said. seems like I saw somewhere,someone made one with foam insulation ? do you think that would work ? I have a sheet of 1/2 " foam insulation, that I could use. kinda like to make it look like a hill or something.
I have a roll of the woodland scenics plaster cloth,to cover the outside with.
so would the 1/2" insulation work ok ? also how high should the opening be,or should I get the portal first,and go from there. and yes it will be Ho scale,if that's any help.

Thanks
Ron

[Reckers]

Ontario,

Good morning! Here's a tutorial, and I'm sure you'll get lots of additional information as the day goes on: http://www.thestorefinder.com/rr/rr_lib_landscape.html

Your tunnel has to provide clearance for: car/engine height + track height + roadbed height. If you have a curve inside the tunnel, keep in mind cars need more clearance than the trucks they ride on, and curves require more clearance than straight track. Also, give some thought to accessability: at some point, you'll want to work on the track, clean it, etc.

[T-Man]

Layered foam or carboard strips stapled and clothed, are the two main methods. Mostly it is sculpted foam.

[ontario mainline]

Originally Posted by Reckers

Ontario,

Good morning! Here's a tutorial, and I'm sure you'll get lots of additional information as the day goes on: http://www.thestorefinder.com/rr/rr_lib_landscape.html

Your tunnel has to provide clearance for: car/engine height + track height + roadbed height. If you have a curve inside the tunnel, keep in mind cars need more clearance than the trucks they ride on, and curves require more clearance than straight track. Also, give some thought to accessability: at some point, you'll want to work on the track, clean it, etc.

seen that before.but never bookmarked it. the tunnel will be in a straight area.no roadbed. ya as far as accessability,I would like to make it,so I could lift it off if I had to.

Thanks
Ron

[Reckers]

No problem. If you're interested in building a hot knife, see this thread:

http://www.modeltrainforum.com/showt...9930#post19930

[Pton46]

Building or even buying (I got one as a gift) great investment (hot Knife). Also get the Sheets of Foam from like home depot or lowes you would use on the exterior of your house. (I got my house done with siding and the crew gave me the leftovers). I framed a tunnel out of that and plaster sheets (Craft store).

[bradimous1]

Originally Posted by Reckers

Ontario,

Good morning! Here's a tutorial, and I'm sure you'll get lots of additional information as the day goes on: http://www.thestorefinder.com/rr/rr_lib_landscape.html

Your tunnel has to provide clearance for: car/engine height + track height + roadbed height. If you have a curve inside the tunnel, keep in mind cars need more clearance than the trucks they ride on, and curves require more clearance than straight track. Also, give some thought to accessability: at some point, you'll want to work on the track, clean it, etc.

out of curiousity... when looking at this link, I notice that this method leaves no way to get to the track when under the tunnel... is this an OK practice? I feel like the only things that can happen in this circumstance would be bad... thoughts please as I am starting my tunnel soon and this seems way easier than the way I was planning on doing this.

[tjcruiser]

Hi Ontario,

My kids LOVE our HO tunnel ... they sneak around the back (unfinished side) and peek through my little access windows to watch the trains go by.

I built ours out of 2" pink-stuff insulation foam. I rough-cut the individual pieces to size, first (some setback with each layer), then glued them with foam adhesive (from Home Depot) but also hot glue to achieve a quick grab. I carved with some fine-tooth hand saws and a sharp knife, and added a bit of rough "rock" texture by "whacking" it all over with a 50-grit sanding drum mounted on my drill. Then, paint to suit, and maybe add a little plantlife, etc.

I mentioned the backside access windows. In addition, our whole mountain/tunnel lifts off (upwards) for full access / portability.

I used some store-bought tunnel portals (foam, I think). I used my same 2" drum sander to carve an arch to the top-inside of the tunnel for the first several inches of tunnel depth, and painted it black for a semi-realistic look.

I screwed up a bit on the tunnel inside height, though. (My tunnel had a track ramp inside, so the inside height varied a bit.) I had previously measured the max height of my locos, and then mapped out the tunnel foam layout to that. All good, right? Well, when all was said and done, I hooked up several cars -- including a caboose -- and had our ceremonious first-run. Whack! Turns out, the stove smokestack on my caboose was my real high point. Dohh!

(I'm embarrased to say that I chop-shopped the caboose smokestack, rather than modified the tunnel height!)

Ohh ... word of advise when cutting the pink-stuff foam. It kinda gets everywhere, so do it in a blocked-off room where cleanup is easier.

Ohh ... one other tip (learned here, myself) ... If you paint your foam directly, you'll likely want to use latex (or acrylic) paint, only, as oil-based paint will disolve the foam surface.

Good luck!

TJ

[Stillakid]

TJ, now you've got me thinking I might be able to make a tunnel

I remember when I was a kid, one of our neighbors dad made him 2 tunnels at the same time. He used a big, long, thick balloon, and paper-mache. When it dried, he sawed it in half and had 2 tunnels. He actually made it look pretty cool

[tjcruiser]

Stillakid,

That's actually not a bad idea at all. I never thought of doing that. But ...

When my kids go to the dentist, they walk away with some balloon prizes ... those fat, long ones, like you're talking about. They have about 7 or 8 "humps" along the length ... kinda like rolling hills, now that we're thinking about that. I wonder how large (diameter) you could safely inflate one for paper mache layup?

Not a bad idea at all!

TJ