Reducing the weight of a liftout


ICG/SOU

ICG/SOU

HO & O (3-rail) trainman
Well, progress on my two level rail project continues. One of the issues I discovered early in the planning process was that because the room has two doorways (it was a covered back porch that we walled in and made a home office, so it has a cornerfill doorway from the kitchen straight through to the backdoor, which is also on the same side, cornerfill) that I would need liftouts or swing gates. I went with liftouts since the gates just weren't going to work.

The problem with cornerfill rooms (opposed to centerfill) is that if your track follows all four walls, you end up with your liftout on a curve unless you pull the benchwork away from the walls and that door. Since my wood skills aren't good enough to build curved liftout benchwork, and I was having to build 4 liftouts, I decided the easiest thing for me to do was to build two liftouts, which are almost as wide as the benchwork they attach to.

My benchwork is 1x4s and 3/4" plywood. Above the plywood is 4" of Dow Square edge styrene foam board (2x 2" boards). Since the plywood adds dimensional stability to the frame of the benchwork and liftouts, I was thinking a way to reduce the weight of the liftouts, because they are heavy and cumbersome (one is 31" wide, 44" long, the other is 34" wide and 43" long) to remove and put into place since the layout is at 54" or so above the floor.

My solution is to cut the plywood. In rifle barrels, sometimes flutes are added to a heavier profiled barrel in order to retain the stiffness of the larger profile barrel, but with flutes, they reduce the weight to that of a thinner profile barrel. I thought of using a hole saw to cut a grid of holes in the plywood (and perhaps the 1x4s too) to reduce weight, but to hopefully to maintain some of the positives of using the thicker plywood and such.

Has anyone tried this? Does my idea achieve what I want? Is there another option (besides going to the gym and pumping iron)?

Thanks in advance for the help.
 
Slotting the 3/4 ply negates any and all advantages of the thicker size; the end result is that the stiffness will equal that of the thinnest area.

You'll gain the most by decreasing the thickness of the plywood, 3/8 should be plenty (and everywhere else). 3/4 is way overkill.

Actually for the liftouts, the plywood thickness adds little rigidity, the fact that it is there is all you need. For the liftouts you COULD go to even thinner, 1/4 would work.

Why? Because in engineering terms, the rigidity of the module is more a function of the thickness of the entire module (to a degree). Once glued and screwed to the framing, the plywood's stiffness is moot: the unitized assembly dictates the ultimate rigidity.

A section made of 1x6 with a 1/4 plywood deck is a lot stiffer and lighter than a section of 1x4 and 3/4 plywood deck.

Use lightweight woods and plywood for sure: birch, fir, etc are much lighter than yellow pine for example. By gluing and screwing it all togther, you unitize the structure and make it act as one solid piece. With out glue, the individual parts are subject to separate motion, and that causes a lack of rigidity over time.
 
I went with 3/4" pine plywood since the local lumber yard I didn't have birch or fir, and a couple of local guys said to get a thicker plywood if going pine.

It would have been nice to know the trick of using 1x6s and thinner plywood earlier. I used the Kalmbach book as a guide with input from local guys. I had thought about that plastic attic decking, but didn't know if it would have done the trick.
 
I resorted to 1.5" extruded styrofoam made by Dow..the blue stuff. To help keep it rigid, I layered it using acrylic latex adhesive suitable for use on foam, and girded it using 1X2 running as stringers under the outer nether perimeter running parallel to the major axis. Then, the single girt runs at a right angle across the minor axis at any convenient point to join the two stringers.

It is plenty strong, now into its fifth year. It isn't a lift out so much as a bridge spanning my central operating pit to provide a reversing loop. It is about four feet long, and runs diagonally across the pit. It can be seen in the photo: [It is hinged at the close end with two 1.5" brass cabinet screws, and there are two brass barrel locks at the far end.]

IMG_6186sharadjr.png
 
Have you considered a pulley system? A simple block and tackle would make the section a lot easier to hoist, and you could even motorize it.
 
HMMMM Never thought of the block and tackle approach. Might give it a try if I decide to use the size of angle iron used in highway bridge construction. I was thinking of a 1 inch aluminum angle which might be lighter than the wood that was used.
 
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