Tunnel Linings?

[scott]

What do people use to line the insides of tunnels? I've built a couple (probably poorly) with three sides of a cardboard box forming the sides and roof, but that only works for straight tunnels or short curving ones. I'm going to need to build some longer curving tunnels soon, and I'm wondering what to use.

[Guest ___]

First time through, nothing which I sorely regretted. Now this time, I still use the cardboard, but they are painted black near the portals.

[Bernard]

What I do, Scott, is I take 2 pieces of black foam poster board and score it with an Xacto knife to get it to fold on a curve if need be (or straight but unlikely) then I use the same black foam board to make a top to the tunnel. If it is going to be a long tunnel, make sure you can remove the top of the mountain. To make sure it is black (after messy hydrocal cloth is applied) I will also airbrush black paint on the inside walls. 

I'll see if I have any photos to illustrate what I'm trying to describe.

[scott]

What do you use to attach the tunnel walls to the base?

[CaptOblivious]

I use this thin foam sheet that Midwest makes; it is very flexible, but quite strong. Very much like the core in foam-core. It is very easy cut, and to form into curves to follow curvy track, and then I just put a foamcore roof over it. I affix all of it with low-temp hotglue. But learn from my mistake! Paint it black before you install it!

[Bernard]

Scott- I'm used 3 differrent glues on 3 different tunnels. Liquid Nails for foam projects (takes awhile to set, not my favorite choice) Tacky Glue, one of my favorites, easy to use, and PL-300, it's similar to Liquid Nails but much stronger when working with foam, has a purplish color and smells. Tacky glue is very similar to what product Woodlandscenics sells as their foam glue.

 

I also use straight pins at the base to hold it in place until it sets and will apply a beaded line to the outside of the wall for extra strength because you will be covering the tunnel shell.

Don't bother ballasting the track inside the tunnel, no one will see it. Also, if you have a straight section in the tunnel, it's not a bad idea to put a re-railing track in there, it can prevent a lot of future de-railments.

[Guest ___]

If you haven't made your tunnel yet, I can strongly advise against cardboard for anything.

[scott]

Well, I've already used cardboard in two tunnels, but it sounds like I should try one of these foamboard-and-glue options for the rest. Time for another trip to the craft store....

[disturbman]

If it's just for linings purpose (and not support) couldn't painted/printed paper and some wood/plastic/foamcore strucure or frame be enough?

[scott]

I'm sure that'd be fine--paper by itself I wouldn't trust, but anything strong enough to bear the weight of the newspaper under the plaster cloth should work. I'm just wondering what works *best.* I'd even toyed with the  idea of getting some 4"+ flexible tubing and slicing it lengthwise to make a tunnel.

[disturbman]

Anyway a small illustration of Bernard's way of doing: http://jamesriverbranch.net/part_11.htm

 

The layout is in Z but the process is the same.

[Darren Jeffries]

I'd even toyed with the  idea of getting some 4"+ flexible tubing and slicing it lengthwise to make a tunnel.

 

Somewhere here on the board, there is a thread where someone has done something almost identical to this idea... he modelled a sunken line. looks a little like the LA river but for trains. at each end there are two double tunnels.

[Bernard]

Anyway a small illustration of Bernard's way of doing: http://jamesriverbranch.net/part_11.htm

 

The layout is in 2 but the process is the same.

 

Thanks you saved me from going into my photo files, that is exactly what I was describing.

 

It's always a good idea to have a strong support of a tunnel lining, you will be covering it with foam, hydocal cloth, newspaper, etc. to hide the tunnel liner.