[Webnerdnick]

I have a N scale layout I'm putting in an office. It'll have walls on 3 sides. Approximate dimensions are 90" wide and 80" on the longest side. I have a maximum variance of 3" on the outer track to keep with a 2-2.5% grade.

I was wondering if I was over-thinking benchwork for this scale? I was thinking of doing an L-Girder design, and in the attachment, you can get an idea of how I planned on laying it out. Do you think it's wise to go the route of the L-Girder, with it all being open and just having the roadbed supported, or do you think I should just build flat tables and use foam to build my slopes up.

The flat table route would be MUCH faster, but I was wondering if someone could speak from their experience here.

 

[CTValleyRR]

L girder benchwork is definitely the smart choice.

Open grids have drawbacks. If you have an open grid, you will need something to fill it. Cardboard strips, window screen, wooden lathes, and much more have all been used for this purpose.

I would say just put a layer of extruded foam insulating boards on top of your L girders and build on that. You can carve relief below track level if you need to.

 

[traction fan]

Yes

I have a N scale layout I'm putting in an office. It'll have walls on 3 sides. Approximate dimensions are 90" wide and 80" on the longest side. I have a maximum variance of 3" on the outer track to keep with a 2-2.5% grade.

I was wondering if I was over-thinking benchwork for this scale? I was thinking of doing an L-Girder design, and in the attachment, you can get an idea of how I planned on laying it out. Do you think it's wise to go the route of the L-Girder, with it all being open and just having the roadbed supported, or do you think I should just build flat tables and use foam to build my slopes up.

The flat table route would be MUCH faster, but I was wondering if someone could speak from their experience here.

Webnerdnick;

I think you may indeed be overthinking the benchwork for such a small layout. I should explain that I'm a big fan of L-girder construction to prevent warping, and I often promote it here, and I also use it on my own layout.
However, your layout is going to be in an office, which I'm assuming, is climate controlled. That should minimize the warping, though it won't necessarily eliminate it altogether. The type of wood used, and whether or not it's painted, would also be possible warping factors.
The other advantage of L-girder is its great strength, especially over long spans between table legs.
It is also lighter weight than some of the "really overbuilt" (and underthought) benchwork we see here, A 2x4 grid topped by 3/4" plywood, supported by 2x4 legs!
For the size layout you will have, and the minor weight of model trains in any scale smaller than the live steam, you can ride on it, type, the strength is not needed.
CTValley and I agree on most things, and I think we may, at least in part, basically be recommending the same thing here. A thick sheet of extruded foam.
The supporting structure can be L-girder, but it doesn't need to be the traditional, heavy-duty, 1x4 and 1x3 type.
I use a form of "L-girder" (or "C-girder") made of the 1/4" Luan plywood that I use for sub-roadbed and 3/4" x 1/4" pine strips glued under each side of the Luan. (see photo #3) I'm not suggesting you go that small, since the "span" between my risers is rarely more than a couple of feet, but there are inbetween sizes. My "benchwork" is weird, made up of foam-filled box-girders and arches, supporting a bookshelf top. (see photos 1 & 2)
You also won't need the "stringers" or cross pieces, shown in your diagram, or at least not as many, if you use 2" foam. The cross pieces you do use can also be built between the L-girder outer frame, in a grid. That saves thickness, which is one of the disadvantages of traditional L-girder construction.
My old club used 1x3 & 1x2 L-girders as a basic outer frame and added 1x3 stringers inside this frame in what amounted to open grid benchwork with an L-girder outside frame. The entire benchwork including stringers, was only 3" thick.

Any of the benchwork types we've discussed in this thread, traditional, heavy-duty L-girder, smaller & modified L-girder, or open grid, will work well under a sheet of thick foam. Any will give you the necessary strength to rigidly support your layout, and yet allow you to have the convenience of a flat surface that can be carved downward as scenery demands.

Good luck, Have fun;

Traction Fan :smilie_daumenpos:

 

[Webnerdnick]

Thanks for all the great feedback! I knew I was overthinking it, and really the plan was to probably just do a regular table with 1/2 plywood over top of it, and then use foam for the elevation and scenery.

Based on the feedback, I'll probably build the table frame and then use a 2" foam for the table top and forgo the plywood altogether. If this was going to be a 30' x 30' design and in a larger gauge, that'd be a different story.


I looked at what others was doing and though maybe I should go the cookie cutter route, and it seemed more complex, but had advantages with being able to adjust elevation or use plywood to create smooth transitions.

I'm just concerned about using foam and getting smooth transitions, but I have some ideas. I had also debated using switch machines or manual throws, and I think I'm settled on using manual throws. I just didn't want the challenge of adding switch machines in foam after everything was down and in place.

 

[CTValleyRR]

Switch machines are pretty easy. Drill a 3/8" hole under the head block ties and throwbar of each turnout. Then you can always go back later and retrofit switch machines. I mount mine with double sided tape.

To put the actuating wire through the throwbar, here is what I do: get a 6" length of brass tube with an ID just big enough for the wire. Make a "flag" of tape on one end, so it can't fall the whole way through your layout. Drill out the hole in the throwbar if necessary to that the brass rod fits through it. Mark the underside of the layout to show the where the track is. Center the points and the wire on the switch machine. Feed the tube down through the throwbar and thr hole under it. Make sure it is more or less straight up and down. Then feed the wire up through the tube, check to make sure the portion of the actuating wire is more or less perpendicular to the track, and stick the switch machine in place. Pull the tube out, and the wire will be in the hole in your throwbar. Trim it if necessary so it doesn't snag on passing cars.

 

[CTValleyRR]

For slopes, you can make a wooden template with the correct taper for the slope, and use that to sand foam into the desired slope. Or use Woodland Scenics incline starters and foam panels.

 

[traction fan]

Mounting switch machines under foam

Thanks for all the great feedback! I knew I was overthinking it, and really the plan was to probably just do a regular table with 1/2 plywood over top of it, and then use foam for the elevation and scenery.

Based on the feedback, I'll probably build the table frame and then use a 2" foam for the table top and forgo the plywood altogether. If this was going to be a 30' x 30' design and in a larger gauge, that'd be a different story.


I looked at what others was doing and though maybe I should go the cookie cutter route, and it seemed more complex, but had advantages with being able to adjust elevation or use plywood to create smooth transitions.

I'm just concerned about using foam and getting smooth transitions, but I have some ideas. I had also debated using switch machines or manual throws, and I think I'm settled on using manual throws. I just didn't want the challenge of adding switch machines in foam after everything was down and in place.

Webnerdnick;

CTValley has already given you two good options for creating smooth transitions with foam, and a method for locating, and mounting, switch machines. Here's one more of the switch machine options. I use a very old & reliable linkage system between my turnouts and the motors that operate them. It was once sold commercially under the name "Earl Eshelman linkage" though I make, rather than buy, mine. The photos below show how it works. A piece of steel music wire is bent into a crank that fits inside a 1/16" Dia. brass tube. The tube and wire can be any desired length so penetrating thick foam is no problem. Under the foam the music wire is bent again, and pushing or pulling on the bent part of the wire rotates it and moves the the throwbar & points. So now you have one more option to consider. Caboose Industries manual ground throws are easy to instal and inexpensive. As long as you can reach all of your turnouts, they would be the simplest option.

have fun

Traction Fan :smilie_daumenpos: