Long supportless benchwork?

[daniel_leavitt2000]

My own its to experiment with one module before expending. I'm actually going to do the bench work before having a definite track plan. I can see things in my mind much better than I can adapt to paper.

David, the rear of the module is supported every few feet, it would just be the front part of the valence and first deck that needs to span that 15'. I use all lightweight materials aside from the bench work: foam insulation with a top layer of sculpt mold. I don't anticipate the entire span would be more than 100 pounds.

[nickelplate759]

If the rear is supported, then all you need to do is keep the front from sagging.  If the front "beam" can twist, it will twist and sag - so you need to make sure it can't.

An easy an easy and cheap solution might be steel braces from the rear legs (like big shelf support brackets).   Not the "L" shaped ones, but the bigger, heavier ones that look a bit like right triangles.

[Cajonpassfan]

Actually, if the module is solidly supported on three sides (back wall and "bookcase" sides, you may get away with a relatively light front span.  My upper deck, although much shallower, is built of good quality lumber box frame, glued and screwed, supported on three sides by walls or perpendicular modules. I wanted the upper deck to be as thin as possible to maximize separation between decks, so I tried 1x2's, and I was just amazed how solid the structure is when screwed into the wall and adjacent modules. Yours is deeper, but I would think that two or three 12 or 18" solid steel L brackets supporting key perpendicular joists in the back would provide the rigidity needed, provided your box frame is solid. They can be below deck, or above, depending on your scenery and backdrops.

I'm attaching an in-progress pic of my Cajon layout to illustrate. The front edge of the C shaped upper deck benchwork is totally unsupported for about 28' of run. Note the open corner, solid as a rock. I do have one 10" steel L bracket screwed into the wall and the top of one of the 1x2 joists hidden inside the hill.
Just food for thought...
Sorry about the crappy photo, seems a couple of bulbs have burnt out.
Otto K.

[jagged ben]

Box Beam.  Keep it light.  An example of a box beam is the typical Hollow Core Door (HCD) which is simply built from 5/4 x 5/4 solid wood with 1/8" luan top and bottom glued.  Very light and very stable.  You could use HCD's (2) end to end and tie together with a simple inside and outside rail (like a 1x3) screwed and glued to the door edge.

I like the diorama type setup and since its free standing you could set it up as back-to-back modules in the center of the space rather than an along the wall typical setup.  If you separate them a bit (space between back to back) that may give you room to put in your helix's (or is it helii?)

Cheers,
Craig

This I think is probably the best advice given so far, although I would probably build the box beam from scratch at 15ft, so as not to have a weak point in the middle.

[daniel_leavitt2000]

The first module will be Worcester. The CR yard and Worcester Union Station will be on top and require the whole 30+ inches, but I think I can shrink the lower level to about 18" wide for the P&W interchange. This will let me add supports for the upper level along the rear edge and about 18" set in from the front. I should be able to cantilever the joists. This will also allow for hidden tracks along the back wall of the lower level.

Framingham will be similar. Top level will need to be about 30+" wide, but only 20-24" will be visible. The rest is needed for a return loop to the low3er level. This would only need to be 18-20" visible, so again, I think I can cantilever the joists.

Boston is the biggest concern. Both South Station and Beacon park are massive. Both upper and lower levels will need to be the full 30"wide and 15' long unobstructed. But this will be the last section built so i'll take what I learn from the other modules and apply it here. Also one $400 aluminum angle is much better than 3.

I am also thinking maybe I should build the rear of the layout into the wall to reduce the amount of lumber needed.

[OldEastRR]

I like the diorama type setup and since its free standing you could set it up as back-to-back modules in the center of the space rather than an along the wall typical setup.  If you separate them a bit (space between back to back) that may give you room to put in your helix's (or is it helii?)

Cheers,
Craig

This is a valid idea. If you made back to back modules down the center of your space, you could put helixi blobs at each end plus have another track continue on the same level to the next module. Since the modules would be mirror-images in construction, just bolting their backs together would give you a very stable structure. And leveling legs would keep everything level w/o stress on walls, supports, etc. You still keep the portable aspect and furniture-like appearance, but this way you get almost twice as much mainline on both decks. And with the whole thing freestanding in the center, you have unlimited access for following your train no matter what route you send it on. It looks like you'd have wide aisles on both sides, too.

This is one of those "outside the layout box" ideas.

[cne_craig]

You could eliminate the wood, sculptamold, aluminum angle, foam, plywood and all the costs, tolerances and weight associated with that set of materials and go with 1 material and some glue.  I recommend you look at High Density Urethane board.  Used in a variety of industries.  Here's a link:  http://precisionboard.com/products/high-density-urethane-pblt/ 

You could glue up a box beam and will easily be half the weight,  stronger, stable, and lots of other pluses.  I'll suggest a layup as follows: base sheet 1/2", intermediate edge and inner strips (12"OC) of 1" x 2", Top sheet of 1" thick.  You could probably use the 15 or 20 lb density versions.  Cost wise it runs $125 for 1/2" and $250 for 1" on 4x8 sheets.   I'm sure you could build a 15' x 3' beam with a table saw and glue, and keep the vertical joints offset.  Basically you'll end up with 1 monolithic structure.

I think you'll be disappointed with mixing all those different materials in creating those long structures.

Cheers,
Craig

[mark.hinds]

deleted

[mark.hinds]

My own its to experiment with one module before expending. I'm actually going to do the bench work before having a definite track plan. I can see things in my mind much better than I can adapt to paper.

David, the rear of the module is supported every few feet, it would just be the front part of the valence and first deck that needs to span that 15'. I use all lightweight materials aside from the bench work: foam insulation with a top layer of sculpt mold. I don't anticipate the entire span would be more than 100 pounds.

I like your museum diorama concept; I have been doing something similar. 

Building one test module to test the structure sounds like a good idea.  Steel channels sound promising, they have the best strength-to-weight ratio (I used aluminum channel on my layout).  Keep in mind that secondary benchwork (risers & subroadbed) supporting the actual track, wiring, lighting, models etc. also add weight; it's not just framing benchwork and scenery. 

If you decide to use modern wood or foam products, you might want to research possible outgassing (formaldehyde, etc.). 

The MR Clinchfield project used heavy-duty adjustable bolts on the bottom of the wood legs, to allow leveling.  You could use those as-is for a concrete floor, or with plastic moving sliders under them for a delicate floor. 

MH

[wm3798]

Why not use narrow hollow core doors?  They're 6'8" long, have good frames built in, are fairly rigid, and have a good finished surface for mounting lights etc. to the bottom to light the deck below.  Use a 1x3 or 1x4 to apply a fascia, and you should have no trouble spanning two for a run of 13'4" for longer scenes. 

You can pick up bifold doors at your local ReStore for pennies on the dollar, strip off the hardware, and enjoy widths of 12, 15, 16, or 18".  You can also get single panels from 20" up to 36" deep.  They're lightweight, so they'll mount to wall brackets with ease, and you can laminate 2" foam to the top to create whatever topographical profile above or below the rail you want.

Wiring?  Easy.  Leave a channel at the front edge behind the fascia for your bus lines, and trench your drops into the foam to get to the connections.  2" of foam plus 1-3/8" of door is also plenty to conceal a Tortoise installed below a switch.  Just cut a square out of the door facing to access the wiring board.

Lee

[nscalbitz]

My first choice would be supported box section aluminum. Why would anyone compromise the laws of physics by using 'angle' iron. Hell even a ladder section would do for the base.
You have pricing/ expense problems because of incumbents and lobbying; here we have zero price differential across construction materials because of choice of housing materials in timber, steel or aluminium framing- the operative duopolies cartel to match any other product prices.
regards
dave