Allrighty then! I cut the first of two holes in the wall to run my double mainline through. Obviously I need to do something so that if I get a derailment while passing through, I don't lose the trains in the abyss below. As I'm not a carpenter and I know that quite a few of you are, I ask - what's the best way to finish this off? I'm not concerned how the wall looks from the outside or inside as both will have portals to cover. What I'm at a loss for is what to do in between the two pieces of sheetrock?

I think what I would do is cut the bottom sheet rock on both sides below the roadbed. Then I would make a rectangular frame to bridge both holes, and use some aluminum angle screwed into the frame on each side to keep the frame from moving in either direction. That is undoubtedly NOT the way a pro carpenter would do it, but it seems like it would work, and once you put in the tunnel portals, the fix is hidden. The other method might be to make a "bridge" with plywood and the aluminum angle for the bottom of the holes. Then you install a tunnel liner from portal to portal to seal up the sides, but I'm not sure if a tunnel liner is as strong as the framing would be. By the way for that short distance to bridge the thickness of the wall, 1/8 inch luan door skin material would work fine.

Heavy duty version of those with OCD:

1. Make a rectangular frame to fit flush inside the opening of the hole - that's the "Yawning Chasm of Death". Don't force it or the drywall may bow slightly.

2. Set it below the inside lip so that a piece of plywood and/or foam or whatever, cut to fit, will be flush with the bottom of the drywall opening when sitting on the framework.

3. Place a facing strip on the outside of both sides of the hole flush with the bottom of the vertical openings. This can be thin stripwood if desired, and will be used as below -in #3.

3. Use long drywall screws to screw through the outside strips and the drywall and into the inside frame, thus stiffening and reinforcing the drywall and firmly anchoring your inside platform framework.

4. Now mount your horizontal piece onto your framework, add tunnel, tracks, trains and enjoy!

5.

Quick version: ( for low-stress environment)

1. Take piece of drywall and cover bottom of hole.

2. Screw two thin strips of wood to the insides of the bottom edges of the hole, screwing through from the outside. If you are the worrying type, secure a thin piece of reinforcing material like masonite to the bottom of the drywall hole cover to prevent possible cracking. Drywall is actually pretty tough stuff when it's a small square.

3. Set drywall piece on wood strips and secure.

4. You're finished...

4. Match outside track to level of hole floor and drive on!

1.

What size is the hole? It needs to be sealed up, trust me. Not just for trains, but for insects. My parents used to have a bad cockroach problem. When they remodeled their kitchen, they found where a careless electrician made a huge hole in the sheet-rock behind the wall mounted microwave. the roaches were using it as a portal to the ceiling, and through the ceiling vents to the outside. Since they sealed it up, there haven't been any more roaches in the house.

Depending on the size, I would suggest a few things.
1) You could use a piece of square PVC rain gutter downspout. Shame to have to buy a whole 10' length, but maybe you have one laying around.
2) You could cut the hole round and use a large PVC pipe coupling. Looking at your photo, the wall stud may interfere with that.
3) If you walk down the aisles at home depot where they keep the vent pipes and such, perhaps you can spot something square you can use as an insert. Perhaps a plastic electrical wall box?
4) If you can't find anything to insert inside, you could frame off the inside yourself with 1x4 wood. Cut the bottom 3/4 of an inch longer than the width of your hole. Drill a drywall screw partially into the side to use as a handle to hold it in place while you fasten it inside the wall. Then, put it into the wall, hold it in place using the drywall screw handle, and screw it in place using drywall screws. Do the same for the other 2 sides (the 4th side is the stud), cut off the drywall screw "handles" with a hacksaw, and tape and spackle the edges.

It's not clear if there is a stud on the right side of the opening. If there is, you'll only need to fill the other three open sides. If not, you'll need to do four. I'd just cut the pieces to the right size so they fit snugly on the inside and flush with the sides of the opening (use drywall or maybe 1/2" ply). As the span is quite small I don't think you require reinforcement or screws of any kind. Just use Liquid Nails to glue them to the inside of the walls. You might need a couple of THIN nails to hold them in place while the LN sets. After it's set, remove the nails and paint the inside of the opening a dark color. Then run your track across and place your portals. Make sure that the roadbed and track are a few inches longer than the depth of the opening so they span the opening and are firmly set on either side of the opening. Then, you'll be good to go....

I cant tell what you are using for bench work on the far side but what ever it is when you cut for near side leave a tab when you cut it that will continue into the wall. use something thin to add left side and top inlarge the hole in the sheet rock to accommodate the extra material. now build your bench work inserting the tab with side and top. Finished

Just to see if it works...

Stuff some fiberglass insulation on some newspaper and stuff it into the wall all around the opening. Take a can of "Great Stuff" foam or equal and fill the hole the rest of the way up. Let dry, then take a hack saw blade and recut the opening.

Gary S Wrote:Just to see if it works...

Stuff some fiberglass insulation on some newspaper and stuff it into the wall all around the opening. Take a can of "Great Stuff" foam or equal and fill the hole the rest of the way up. Let dry, then take a hack saw blade and recut the opening.

Sorry, Gary. I had to laugh at your suggestion when you mentioned "great stuff". I was at Home Depot tonight, and they had a demonstration display for the "Great stuff". It was sprayed into a big mound - looked like a big pile of doggie doo. The 14 year old in me got a great idea of how to play a prank on my nephews. I can't wait until I see them next

Go get'em, Kevin!

The "spray can foam" was sometimes used to seal around pipe penetrations on construction sites. For example, a 3" hole in a concrete wall with a 1.5" pipe through it. The space between the hole and the pipe could be filled with foam until it oozed out on both sides, then after it dried, a hack saw blade would cut it flush with the wall. Made for a very neat installation.

Thanks guys... been outta town for a bit... back now.

Kevin, the hole is roughly 3"x3" and you're not lying about the bug problem. We've got a severe scorpion population around here and I will most definitely seal up the entire hole. I had a light switch fixture that wasn't quite sealed in the hallway and we kept finding scorpions there. I finally sealed it up and haven't seen one in that area since. For now, I've got the whole covered with masking tape on both sides until I can finish it off. You watch... I'll pull the masking tape off and I'll have scorpions stuck to it!

Lotsa good ideas here. I especially like the foam idea. It could be quick and easy. I've also got a lot of the 1/8" hardboard left over from the backdrop and fascias that I might use to frame the inside of the opening.

Steamtrains, yes, that is a stud on the right side so I will only need to close up the hole on the other three sides.

Lester, on the other side of the hole, is the inside of a cabinet. The track will be resting on a sub roadbed of 1/2" plywood above the shelf inside. Clear as mud? Let me take a picture to clarify...

I just read my original post about the foam... it should say "take some fiberglass insulation OR some newspaper and stuff it in the hole..."

I think it would be a neat way to seal up the hole. Now, my first inclination was to cut some 2x4s to length, then screw some deck screws (at an angle so you can remove them later) in the wide face of the baord to use as a handle, then place it between the two pieces of sheetrock, and screw through the sheetrock into the 2x4. Remove the handle screws, caulk, and you are good to go!

It appears in your pictures that you have already cut and mounted your road bed. So that eliminates my suggestion. I have done similar things before and with a little forethought it can be very easy

Well, that's a little misleading Lester. Yes and no. On the outside, you can see that I have glued my cork down to the top of the WS risers and it does go right to the edge of the wall opening. However, that section of the layout is not screwed to the wall yet and can still easily be pulled out to modify. On the inside, as of right now, the plywood sub base is anchored down by gravity alone and the Kato Unitrack is simply sitting on top of that. Nothing has been permanently affixed as ofyet. I still need to calc my grade on the inside of the cabinet and fine tune the opening in the wall to match. Soooo, with that said, it would be quite easy to modify things to the way you have suggested.

I guess I am still in the running then .Whatever you decide to do do it right. That is the last place you need trouble.

Next time, drill a large hole with a hole saw and insert a piece of PVC pipe. It will save all this trouble and concern. 8-)