Layouts and layout building

rob.m:

thanks for the advise. my plan is for an around the wall layout with a solid top with 2" foam over plywood. could i make a simple square frame with supports using 1x4s instead of 2x4s and 1x4 legs

Hi Rob.

Consider the depth of your layout to determine how much support you'll need in the middle of your simple square frame for supporting the plywood. If it is shallower than 18 inches, you probably don't need any.

Yes, you could, and would be best, to use 1 x lumber for the simple square frame.  1 x is much easier to screw together and tends to untwist when screwed, unlike 2 x stuff.  I would use 2 x 4 for the support legs, and make another 1 x simple square around the legs (inside the legs on the ends) about 1/3 the distance of the leg above the floor.  This will keep the legs from shifting when kicked and will also provide you with support for another shelf below the layout that you could use for storage.  No need for gussets or 45 degree leg support pieces with the other ribbon of 1x around the lower part of the legs.  2 x 4 for legs works well since you'll be screwing into them, rather than screwing them into something else.

I haven't built that many layouts, but I tend to agree with Jim.  It sure does seem like a lot of work to make all of those little L-girders. 

Doug

I built my first layout using 2 X 4 and 5/8" plywood as a surface, and it was a huge table...not two ways about it.  AND HEAVY!!!  but I could get up and reach all parts of that layout during construction.  In fact, I spent as much time on the layout as off it by the time I was doing the foam carving and the eventual track laying and scenicking.

I have no regrets, but I elected to purchase 1 X 4's and rip them with a table saw this time around.  The full 1 X 4's were great for one element of L-girders, and the ripped halves comprised either the other element in the L-girders or joists, risers, diagonal bracing....highly versatile and much lighter...less filling.  I found that this lighter construction was just fine for getting up on it, and must say that it will be my preferred method....although Chuck's materials and method sounds intriguing.  If you can modularize metal construction, you could move such a layout from place to place with relative ease.

-Crandell

Well this comment will defy logic but it is true.  An L girder is much stronger than a 2 x 4.  Similarly a 1 x 4 box beam is much stronger than a solid 4 x 4.  The reason is the same prinicpal as an I beam.  If you picture a weight in the middle of an I beam the maximum compression and stretching is where the flanges are.  That's the reason for wide flange beams with very thin webs.  the web is useless for anything other than alligning the flanges.  You can span a much longer distance between legs with L girders than solid wood.  If you don't believe this make up an L girder and 2 x 4 of the same length and support them at the ends.  then have somebody measure the distortion when you stand in the center of each. I don't have a problem with using 2 x 4s  just bad engineering information.

Yup, minimizing deflection is the key when working with long thin spans of lumber.  L-girders out of 1 x minimizes it better than simple 2 x.  But deflection isn't the problem with legs. With 48 inch or taller vertical spans like legs, the key is to minimize the impact of blunt horizontal force along the bottom.  Use L-girder, 2x2, or 2x4, for legs, it doesn't matter, the same problem exists.  The ribbon of 1x about 18 inches off the ground works well and provides the additional shelf.  I'm assuming Rob is planning on having several long, shallow table tops abutting the wall, unless he chooses to do the shelf bracket method.

I've seen articles on building a layout from the ground up, where the bench work is a web of L-girders, meticuously fashioned from ripping a 4x8 piece of plywood into 3 inch strips, then placing a table top on the whole thing.   It doesn't need to be that complicated.

Don't forget, the table top itself provides great rigidity to the structure when it is finally attached.

Doughless:

Yup, minimizing deflection is the key when working with long thin spans of lumber.  L-girders out of 1 x minimizes it better than simple 2 x. 

Not necessarily.  Deflection is minimized primarily (but not only) by depth of the structural member.  A 2x4 will resist deflection better than a 1x4.  If the L-girder is comprised of a 1x4 with, say, a 1x2 or 1x3 on top, it might be equal to or better than the 2x4 because of the extra depth (I haven't troubled to do the calculation).  But I believe a 1x3 with a 1x2 or 1x3 on top will deflect more than a 2x4 (on edge, of course).

Doughless:

Yup, minimizing deflection is the key when working with long, thin spans of lumber.  L-girders out of 1 x minimizes it better than simple 2 x.  But deflection isn't the problem with legs. With 48 inch or taller vertical spans like legs, the key is to minimize the impact of blunt horizontal force along the bottom.  Use L-girder, 2x2, or 2x4, for legs, it doesn't matter, the same problem exists.  The ribbon of 1x about 18 inches off the ground works well and provides the additional shelf.  I'm assuming Rob is planning on having several long, shallow table tops abutting the wall, unless he chooses to do the shelf bracket method.

Long, thin spans of anything that's loaded laterally and not braced!  Legs are loaded longitudinally, in compression.

The ribbon of 1-by doesn't help much in combatting side thrust, and makes the space under the benchwork useless for roll-out storage units.  I personally prefer angled braces - less material, less wasted space and you can't distort a triangle unless the fasteners fail.

Unless there's some aesthetic objection to wall fastenings, narrow shelves are a lot easier to deal with if they're on shelf brackets.  Mine are, even though they support multiple levels of track.

I've seen articles on building a layout from the ground up, where the bench work is a web of L-girders, meticuously fashioned from ripping a 4x8 piece of plywood into 3 inch strips, then placing a table top on the whole thing.   It doesn't need to be that complicated.

As a firm believer in the KISS principle, I cringe every time I hear that!  One reason I like steel studs is that the screwing flanges are either built in or can be created in seconds with tin snips and vice grips.

Don't forget, the table top itself provides great rigidity to the structure when it is finally attached.

Depends on how the table top is made, and how it's attached.  Thin cookie-cut plywood, with lots of wide open spaces, won't win any prize for rigidity.  On (under) my big peninsula, a diagonal lightweight stud screwed to the L-girders and the bottoms of the joists changed the stiffness coefficient from tofu to granite.

Aside to Crandell - Steel stud construction lends itself nicely to modular construction.  In fact, the first MRR article I noticed on the subject was on assembling a group of small module frames.  Studs retain the L-girder convenience of having lots of 'comes with the territory' screwing flanges even when assembled like a miniature stud wall.

Chuck (Modeling Central Japan in September, 1964)

ndbprr:

An L girder is much stronger than a 2 x 4. 

I have to disagree again. A beam's effectiveness is based on two things: strength and deflection.

Strength is a function of a beam's section modulus. The higher the S value, the lower the stress in the beam. So a beam with a higher value of S is stronger and can carry more weight.

Deflection is a function of a beam's moment of inertia. The higher the value of I, the lower the deflection.

Here's a comparison between An L-girder ripped from a 1x4, a 2x4 set on edge, and a 2x4 laid flat:

                                               I                                S

L-Girder                                1.42                            .95

2x4 Vertical                           5.36                           1.42

2x4 Flat                                 0.99                           1.31

So a 2x4 on edge is nearly twice as strong and four times stiffer than an L-girder. A 2x4 laid flat is a little less stiff but able to carry more weight than an L-girder.

And yes, I'm a structural engineer by trade. So I get pretty geeked up about this kind of stuff.

mononguy63:

ndbprr:

An L girder is much stronger than a 2 x 4. 

I have to disagree again. A beam's effectiveness is based on two things: strength and deflection.

Strength is a function of a beam's section modulus. The higher the S value, the lower the stress in the beam. So a beam with a higher value of S is stronger and can carry more weight.

Deflection is a function of a beam's moment of inertia. The higher the value of I, the lower the deflection.

Here's a comparison between An L-girder ripped from a 1x4, a 2x4 set on edge, and a 2x4 laid flat:

                                               I                                S

L-Girder                                1.42                            .95

2x4 Vertical                           5.36                           1.42

2x4 Flat                                 0.99                           1.31

So a 2x4 on edge is nearly twice as strong and four times stiffer than an L-girder. A 2x4 laid flat is a little less stiff but able to carry more weight than an L-girder.

And yes, I'm a structural engineer by trade. So I get pretty geeked up about this kind of stuff.

Doughless:

mononguy63:

ndbprr:

An L girder is much stronger than a 2 x 4. 

I have to disagree again. A beam's effectiveness is based on two things: strength and deflection.

Strength is a function of a beam's section modulus. The higher the S value, the lower the stress in the beam. So a beam with a higher value of S is stronger and can carry more weight.

Deflection is a function of a beam's moment of inertia. The higher the value of I, the lower the deflection.

Here's a comparison between An L-girder ripped from a 1x4, a 2x4 set on edge, and a 2x4 laid flat:

                                               I                                S

L-Girder                                1.42                            .95

2x4 Vertical                           5.36                           1.42

2x4 Flat                                 0.99                           1.31

So a 2x4 on edge is nearly twice as strong and four times stiffer than an L-girder. A 2x4 laid flat is a little less stiff but able to carry more weight than an L-girder.

And yes, I'm a structural engineer by trade. So I get pretty geeked up about this kind of stuff.

That's interesting.   Not to keep a dying thread on life-support, but would a girder made from a 1 x 4 and a 1 x 2 be stronger than a 2 x 4?  I'm not sure the girder in your example is the same size as the 2 x 4. 

 

As stated above, the strength is not a major factor because a framework of 1 x 4 will easily support most model railroads.

The reason for the development of the L-girder (yes, I'm old enough to remember that) was to take advantage of the strength of the grain pattern in the wood. For example, on a 1 x 4, it's easy to make it flex on the 1 inch thickness but difficult to make it flex on the 4 inch side. Plus, there is normally more tendency to warp on the 1 inch direction. By taking two pieces of 1 by lumber and forming an "L" with them, their strong directions will support the weak direction of the other piece. Plus, by opposing the grain by 90 degrees, they will minimize the chance of warping.

I used 2 x 4 framing on my layout, but it's built on top of a storage shelf, which is the reason for the heavier lumber in my case.

Rob,

Having built layouts since the mid-'50s, I have used a number of different benchwork construction methods.  My large Chicago basement Lionel layout (8x20) was built with "begged, borrowed, & late night acquisitions" as there was little money for buying wood.  I used 2x4s for legs.

My second larger HO layout (16x8), built in a Joliet Illinois basement in the early '70s used 2x4 legs & 1x4/6 for bracing.  That layout was a "rock", and portions of the benchwork survived two moves and served as a workbench frame thru 2007! 

My last two HO layouts (11x15) have been built with 2x2 legs and 1x2-4 bracing.  These layouts were built in a spare climate controlled room here south Texas, and have worked out beautifully.

Ok, that's some of my layout history, and let me give some of the reasons for doing what I did.  I used 2x4s on basement layouts because they were available, and I didn't have the "fancy" tools that I have now.  By that I mean cordless drills for deck screw fasteners, various powered saws, clamps, and the like.  The base was very strong and durable and seemed to be OK for a basement layout.

Here in a finished room, I considered 2x4s to be too heavy and gross overkill for the layout base.  I used 2x2s, and have 52 of them for legs under my 11x15 layout which pretty much fills the room - except for the center.  Note that straight 2x2s have to be hunted at the local lumber yards, but they are easier to handle, lighter, and if properly braced, they are very strong.  I weigh 225 and can go anywhere on the layout without fear of breaking anything (including me).

Hey, use what works - or what you can get.  Just make it sturdy and solid and ENJOY !!!!

Mobilman44 

It's sort of like using a sledgehammer when a tack hammer would do. I do however prefer 2X4's with a lap joint that will be flush with the L-girder horizontal members. This also makes for easy corner angle brace attachment. I guess I just didn't feel comfortable with 2X2, which would mean sawing  a 2X4 lengthwise anyways as local lumberyards here don't carry 2X2's.  My benchwork will more than support my 180 pound weight.

Verrrry interesting!

Would someone include a photo of their L girder and frame....and maybe why the wiring etc. is simpler with this lighter lumber.  I am about to get to building another layout and, sorry, haven't done the research yet.  And I am a iffy carpenter. 

I do not subscribe or have access to train mags for ideas, but I will be searching for online info soon.

Thanks

mobilman44:

I used 2x2s, and have 52 of them for legs under my 11x15 layout

By "legs," I envision the vertical pieces that hold the layout off the floor. Are you talking about the same things? Fifty-two legs for an 11x15? That's a forest!   It would certainly hold the layout up, though. My layout is 9x17 and has two sides supported directly off of the wall and only seven other legs.

When the time came to assemble my mountain division, I needed a table eight feet wide by 36 feet long.  To support it I fashioned two "T" girders 36 feet long using two 1X4's and supported them with five 2X4 legs seven feet apart.  On top of this structure I laid 1X4 joists and screwed them to the T girder flanges on 24" centers and laid half inch plywood on top of that.  My specifications would be considered underbuilt by most model railroaders but it supports my 200 lbs just fine.  2x4's and 2x3's in the form of reject studs can be had in the trash pile and/or dumpster at any building site so the price is right.  Just make sure to go in daylight and ask the boss carpenter for permission to raid his trash pile.