SpaceMouse wrote: Selector,I hate to break this to you, but what you are showing me is a box-frame construction to which you've added horizontal pieces (which add a little stability). Not that this is bad, but you are arguing apples vs apples. Edit: I missed Mark B.'s last post. He picked-up on it before I did.
Selector,
I hate to break this to you, but what you are showing me is a box-frame construction to which you've added horizontal pieces (which add a little stability). Not that this is bad, but you are arguing apples vs apples.
Edit: I missed Mark B.'s last post. He picked-up on it before I did.
You are absolutely correct, Chip...it's a box frame. Except that, instead of 1X4, the long parallel members are L-girders which make the whole very much stronger along the major axis than had they been mere 1X4's. I wanted this as light as possible, and 1X4's are light, but not terribly strong as stringers go. So, I tried L-girder. Not necessary on the frames, but they sure came in handy under that 5/8" yard module. Very solid support mid-way for an otherwise saggy plywood.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
I adapted the 1x6 simple frame construction that was in use at Dunham Studios when I worked there (the best job in the world! Thanks Clarke), except I used 1x4s as my around the wall layout's max depth is 24" except for the yards where I did use 1x6. Everything was topped with 1/2" CDX ply and then with 2' foam. All joints were glued (carpenters yellow glue) and screwed. The foam was attached with regular liquid nails and held down with 3" drywall screws until dry afterwhich the screws were removed and reused. I believe they use a latex contact cement to attach the foam at Clarke's now, which I would too, but I'm done with that part. The whole thing has been extremely stable for the past 7 or 8 years.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
I just wanted a longish span of two parallel girders under my yard, which fits, I am embarrassed to admit, on one sheet of 5/8" ply. I didn't want a set of supporting legs midships since the plan, according to She, was for storage under the layout, and too many legs would make it awkward to store the large 130 liter Rubber Maid bins that we use for our 4.7 tons of Christmas "stuff". So, I wanted strength, but not the additional height that the usual L-girder and joists atop them would take. If you can see well enough by the photo below, this is what I came up with. As I said, where it seemed prudent to include a diagonal "joist", I cut it at placed it. These were also desired for the extra rigidity in a box frame, of which the L-girdes comprised two long sides for each of the four modules.
First image is the plywood yard. Now that it is bolted to two modules on either end of it, each at right angles, I could get rid of the braces and legs and probably still have plenty of strength...maybe I should defer to you on that...
This next image was taken as I was building spline roadbed. You can see how it all went together, but the risers give the...um, rise...and the joists are nestled out of the way.
What else do I get out of this...maybe nothing...I just felt that this would work, and be strong enough to withstand disassembly. It will take some unbolting, some cutting of plaster terraform at the seams, and cutting some wire. The rest will be horse work getting each module upstairs after the legs are removed. Maybe I am dreaming. Wouldn't be the first I'm sure.
From what I recall reading old MRs and Model Railroading with John Allen, most of Allen's benchwork was finished before Wescott developed L-girder benchwork (please let's not argue over who developed L-girder benchwork - from what I read Westcott was given credit for it - or maybe I remember it wrong). From looking at his construction photos in the book, most of his benchwork was basically built to his basement topography, and took most of its strength from the walls and floor. When the section being "rescued" was lifted away, the benchwork wasn't stable on its own, and collapsed when moved (a tragic loss, IMO).
The big advantages of L-girder as Westcott described it was that 1) no precision cuts were needed, since joints don't butt together, and 2) easy free-form layout edges, since the joist ends could be a long as desired, rather than butt against side girders as in grid construction. One of the big drawbacks, of course, is the total depth of the benchwork becomes significant.
This is classic L-girder construction:
Selector - it sounds like you have adopted something of a hybrid between classic L-girder and grid benchwork (grid benchwork, by the way, is significantly more stable than L-girder, though not quite as strong - but way more than ample for model railroading in any case). I'm curious - what does the inclusion of L-girders in a grid type construction gain for you? There is some enhanced rigidity to the structure because of the L-girder in place of flat girders, but is there something else as well that I'm not seeing? I'd like to know, since I'll need to minimize the thickness of my top deck benchwork so was planning on using grid construction there.
Mark P.
Website: http://www.thecbandqinwyoming.comVideos: https://www.youtube.com/user/mabrunton
Mark, thanks for that. I have no engineering background, but even I could see a problem with the arrangement you described, and which I saw when I was researching L-girder and cross-beams atop them. It seemed wacky, to my way of thinking, so I placed all my joists between the parallel L-girders, even some that were diagonal for riser orientation. I can't help but have much more confidence in that configuration. For one thing, it reduces all that extra height from the joists atop the girders, but it creates a much stronger box-shape, preventing the girders from wanting to reorient themselves under load as you have aptly described. I cannot claim that my way is hugely superior, but it is/must be substantially so.
The gentleman with whom I was just discussing the matter relates how John Allen's benchwork self-destructed upon and attempt to move it. I don't doubt this story at all, why would I, but could it not simply be that the late great J. Allen did not build his L-girder bench in a sound way in the first place? If he made some false assumptions about their best use, then it is no wonder the result this gentleman describes.
The L-girders themselves are actually very strong. The joist installation on top of the girders is what's weak.
An L-girder is basically a built-up 90-degree angle. The way we use them for benchwork is not very efficient from a load-bearing ability point-of-view. As they're arranged, adding load makes the beam tend to twist into it's minimum strength orientation - something a bit less than 90 degrees off it's usual orientation of large flange vertical (that min-strength angle depends mainly on the relative widths of the flanges and strength of each of the flanges). Making the L-grider into a T-girder would significantly reduce that tendancy,and make the entire girder much more stable. The reason the L-girders don't twist and bend is because they're so lightly loaded in our application (even a couple hundred pounds of layout across an eight-foot span is light loading compared to what the girder can actually handle) - a result of needing to effectively eliminate deflection in the beams).
As I said above, the joist installation is what's weak. Screws are tension fasteners (they're designed to take a tension load along the axis of the screw). They're generally very weak in shear (loading at 90-degrees to the axis of the screw - sliding two blocks along their mating surfaces is a shear action) and bending (just what it sound like - bending the screw), unless they're specially designed to handle those forces. Drywall screws, which most of us use, are tension screws.
So here we go, laying a joist on edge across our L-girders, then screwing through the top flange of the girder and into the joist. If we put a heavy load on the center of the joist, it will try to twist into its minimum-strength orientation (lie down flat on the girder), and what is resisting this tendancy is bending stress in the screws, which of course were not designed for that. So the screws will break pretty early on in the loading of the joist, and the joist will fall over and break in the middle. What makes the joists work the way they do is two things: first, that there are several joists tied together on the top with roadbed and scenery supports (like plywood sheets for towns, for example), thus spreading the bending loads in the screws to several sets of fasteners, as well as having joists tending to fall in opposite directions (which way they tend to fall depends mostly on how the grain runs through the wood), thus often canceling the bending forces between sets of joists; and second, that oh-so-helpful light loading when compared to what the benchwork can really handle.
So that's why L-girder benchworks works so well.
Sorry for the dissertation - I get carried away with things like this.
selector wrote:It is simply false to assert that L-girder benchwork is neither strong nor portable. Please elaborate for us so that we can understand why you make that claim. Although, it will be most difficult for me to reconcile what you say with what I use for a layout currently. I can, and have, walked, crawled, knelt, and jostled all over my twin 8' parallel spans and have not had a single indication that they are "inherently" weak.
To each his own, Selector! I know L-Girder has beeen around for eons, but that makes it neither strong nor portable. John Allen thought it was the way to build too, and his layout was lost when an attempt was made to move it after his death. If you had been asked to repair as many L-Girder and plaster layouts as I have, you'd understand why I build the way I build. The bottom line, though, is that if L-Girder works for you that's all that matters. This is a hobby, after all.
As regards turnout installation, we've standardized on the PECO system which places the switch machine under the turnout at the points and gives absolute electrical contact at the points. If you provide slip track connectors at the heel of the turnout any time you need to service it all you have to do is slip the connectors and lift it out for service.
Happy Railroading,
clarke@dunhamstudios.com
Risers on plywood "platform".
On my layout, I used the cookie cutter method for construction. I first built a "platform" of 3/4" plywood on 2X4's, basically built as a wall but horizontal. Both the platform and the risers were built out of 3/4" plywood. I did this both for strength and the resulting smoothness I'd get on the vertical transitions for the risers. Lets face it, you simply cannot do anything quickly using 3/4" plywood, which is desired for a vertical transition. As some commented it may be overkill, but so far I haven't regretted it. It also makes it so that if you cut a riser to the wrong height, you find out about it immediately when the other risers don't fit.
Second, I laid out the design full-sized using plain white paper covering the layout. This laid out both the trackage as well as the required widths of the elevated track sections.
I then used this full-sized drawing, cut into templates, to cut the elevated track sections, along the longest pieces of plywood available. I used the same templates to cut the 1" blue foam to overlay the elevated track sections. This kept all of the really messy cutting in the garage. The blue foam was glued to the plywood.
The risers I cut out of scrap 2X4's, finish nailed from the top and bottom, and glued. Typical spacing was 16" to 18". Where I put a switch machine on the elevated track (3 of them) I cut a nice sized access hole through the platform to get to it. On one I had to shift the riser off to one side and adjust it's height accordingly.
The heavy plywood does make it a bit tougher to cut in the slots for a tortoise switch machine, but it's not that much harder.
To install a tortoise, use 0.30 piano wire, available from your local piano repair parts store. I've got a guy that will sell it to me for $0.10 per foot, in 10' pieces. It's stiffer than the original stuff, and works much better on those longer reaches to it. From the tortoise to the switch it's close to 2" on my layout.
My trackwork is smooth, and it's hard to tell where the vertical curve starts.
Mark in Utah
Nick68 wrote: Second question: How do you mark reply text in a yellow box to indicate the message you are replying to?
Second question: How do you mark reply text in a yellow box to indicate the message you are replying to?
>>With a plywood platform you can place them exactly where they need to go, (as opposed to using the nearest joist.) I do grades by cutting risers of incremental height, calculating the distance of the rise, dividing by the number of risers and spacing accordingly. I pop them in with a nail-gun and the grade is very smooth and even without a lot of time or
I hate to be a bore but I assume that you are using 3/4" wood blocks for risers and that you are popping in the nails from beneath the platform? Do you also slope the top edge of the riser to match the grade of the track? Do you use plywood or solid wood as the bridge between risers?
bogp40 wrote: I see how this can have an advantage. Especially if foam risers etc are used. The only problem I see is that any elevated track having switch machines would have very awkward access if at all. Then provisions for some access to replacement or adjustment should be made.
I see how this can have an advantage. Especially if foam risers etc are used. The only problem I see is that any elevated track having switch machines would have very awkward access if at all. Then provisions for some access to replacement or adjustment should be made.
With foam you would have a problem. With the wood risers and cookie cutters, you only have the risers at most every foot or so. You can work around a switch machine easily enough. I defiinately leave openings for all kinds of access--to tunnels, turnouts, etc.
SpaceMouse wrote: Nick68 wrote: >>The system consists of a unitized platform that may be square or may have many angles to mate with other sections (just like a layout). It is traditionally a box frame with 1x6 (read that as 3/4" x 5-3/4") dimensional lumber or plywood.<<If you use this type of box/platform construction how do you add risers to achieve different levels of track?With a plywood platform you can place them exactly where they need to go, (as opposed to using the nearest joist.) I do grades by cutting risers of incremental height, calculating the distance of the rise, dividing by the number of risers and spacing accordingly. I pop them in with a nail-gun and the grade is very smooth and even without a lot of time or effort.
Nick68 wrote: >>The system consists of a unitized platform that may be square or may have many angles to mate with other sections (just like a layout). It is traditionally a box frame with 1x6 (read that as 3/4" x 5-3/4") dimensional lumber or plywood.<<If you use this type of box/platform construction how do you add risers to achieve different levels of track?
>>The system consists of a unitized platform that may be square or may have many angles to mate with other sections (just like a layout). It is traditionally a box frame with 1x6 (read that as 3/4" x 5-3/4") dimensional lumber or plywood.<<
If you use this type of box/platform construction how do you add risers to achieve different levels of track?
With a plywood platform you can place them exactly where they need to go, (as opposed to using the nearest joist.) I do grades by cutting risers of incremental height, calculating the distance of the rise, dividing by the number of risers and spacing accordingly. I pop them in with a nail-gun and the grade is very smooth and even without a lot of time or effort.
Modeling B&O- Chessie Bob K. www.ssmrc.org
I guess I'd better jump back in here. I did mean "never use L-Girder benchwork". It has no inherent strength and is not portable. [Yes, you can, and probably will, argue that forever.] The platforms and support systems we use are taken from my many years as a Broadway Stage Designer. Every stage set is built using some form of this system because it has to break apart invisibly, go into and out of trucks and then go back together again just as invisibly without falling apart.
The system consists of a unitized platform that may be square or may have many angles to mate with other sections (just like a layout). It is traditionally a box frame with 1x6 (read that as 3/4" x 5-3/4") dimensional lumber or plywood. Everything is glued and nailed (and blocked in the corners when necessary). We actually cut our 3/4" plywood framing to 5-1/4" so as to acheive a six inch thick platform employing a 1/2" plywood top. The result is a layout section that three men can stand on (and do). This platform is generally framed with spreaders every sixteen inches to two feet depending on the weight the unit is to carry. Our base frame is also right from the theater and consists of 1" x 2-1/2" 3/4" plywood framed on edge and faced on the front with T-111 decorative plywood. Each base unit is 32" high giving a typical layout height of 40" when you add two inches of styrofoam to the plywood platform. It also provides a completely finished skirting for the layout complete with access doors. On the rear of the layout (assuming that it's not an island-style layout where there is no "back"), the inner open frames are solidified with triangular 1/4" ply "corner blocks" approximately nine inches on a side and cut on the diagonal of the ply for greater strength and then screwed or bolted to the next frame. The outer frames are held apart with "gates", that is, cross frames built in the same fashion or simply with 1 x 6 spreaders at the top of the frame if the separation between frames is minimal. If the layout is to be built using the cookie cutter technique the styrofoam may be abandoned in the trackboard areas, though we have often reduced the styrofoam to one inch and attached it to the trackboards with Mastic paste (a wonderful "do everything" material). Boy does that styrofoam make a quiet-running layout. This technique works for us and it ought to work for everyone else who wants to try it. I promise you you will never use another "L-Girder" once you've done it this way. If you want to see the assembly of a layout built this way go to our website (www.dunhamstudios.com) and read the "How we do it!" article on the top of the home page.
Happy railroading,
bogp40 wrote: pennsy-gg1 wrote: ..."If we have any "secrets" about how we do it they are very simple ones: never use L-girder benchwork and do use very well supported sectional platforms." Clarke:Thank your professional insider's perspective about benchwork and platform tops. I do have one question(s) about your statement of "never use L-girder benchwork and do use very well supported sectional platforms"... Why and are you suggesting a "box like" or "multi-box like" sectional platform? What are your suggestions for section or box thickness? Suggested size of the boxes and sections? Are they squares or rectangles? Any other suggestions are greatly appreciated. And of course, I could go on ad nauseam Guess I better not! Thanks for jumping-in! I would like you to elaborate, if you will, your reason for not using "L" girder. My club is building a fairly expansive layout (50'x120') with various divisions running at different elevations with most of the subroadbed pine spline. Some is cookie cutter and the facia wanders and curves. In my opinon and as a finish/carpenter, I feel that we have picked a construction system that works quite well.
pennsy-gg1 wrote: ..."If we have any "secrets" about how we do it they are very simple ones: never use L-girder benchwork and do use very well supported sectional platforms." Clarke:Thank your professional insider's perspective about benchwork and platform tops. I do have one question(s) about your statement of "never use L-girder benchwork and do use very well supported sectional platforms"... Why and are you suggesting a "box like" or "multi-box like" sectional platform? What are your suggestions for section or box thickness? Suggested size of the boxes and sections? Are they squares or rectangles? Any other suggestions are greatly appreciated. And of course, I could go on ad nauseam Guess I better not! Thanks for jumping-in!
..."If we have any "secrets" about how we do it they are very simple ones: never use L-girder benchwork and do use very well supported sectional platforms."
Clarke:
Thank your professional insider's perspective about benchwork and platform tops. I do have one question(s) about your statement of "never use L-girder benchwork and do use very well supported sectional platforms"... Why and are you suggesting a "box like" or "multi-box like" sectional platform? What are your suggestions for section or box thickness? Suggested size of the boxes and sections? Are they squares or rectangles? Any other suggestions are greatly appreciated. And of course, I could go on ad nauseam Guess I better not! Thanks for jumping-in!
I would like you to elaborate, if you will, your reason for not using "L" girder. My club is building a fairly expansive layout (50'x120') with various divisions running at different elevations with most of the subroadbed pine spline. Some is cookie cutter and the facia wanders and curves. In my opinon and as a finish/carpenter, I feel that we have picked a construction system that works quite well.
Bob K.:
Just to clarify -- I was quoting Clark and asking him the same question about L-Girder BW. Sometimes the "Quote" button (or maybe me) doesn't work right and can become confusing! As it did in my previous post.
Pennsy
A Model Railroader's Credo: Now faith is the assurance of things hoped for, the conviction of things not seen.
bogp40 wrote:Large layouts with 40-50' long peninsulas having curving and wandering facias, rounded peninsula ends with up to 60" radius are actually better built w/ "L" girder or any form similar. The "L" girder arrangement can change w/ the shape and angle of the plan. Rounded corners done with the crossmembers set on a radian allows for risers to be somewhat perpendicular to the tracks subroadbead.
I can see your point. I would probably take this on a section by section basis and build what is appropriate. I've been known to mix and match on occasion.
I think the specs should reflect the design.
L girder construction isn't needed on a true cookie cutter with narrow risers because the flat top will add stability over a shorter span. If you're talking open grid construction, L girders are needed to prevent the sideways sway that's absent when fastening to a plywood top.
For the record, my cookie cutter is constructed of 1/2" plywood, 1x4 and 1x3 pine on 12-16" centers, and 10" span on risers. My goal was to keep it durable and light weight, as it's intended to be mobile. I could have gone 3/8" plywood, but the extra rigidity of 1/2" was worth the weight in terms of scenery support. It is very strong, and I think I made a good choice of materials for what I wanted.
I also think that going with shorter centers rather than thicker plywood should be looked at, providing you use quality lumber. 3/4" plywood will warp too, over time. Your frame is what dictates the long term quality of what you build.
SpaceMouse wrote: First of all, I can't believe this thread has gone on so long. Second, listen to Clarke. I've spent 20 years in construction and what he describes is the plan I came up with for my layout. Not that it is the only way to skin a cat, as selector and others have pointed out. But, what Clarke describes is the cheapest and easiest way to get it right. I never did get the L-girder thing. To me it seemed like a massive waste of lumber and time.
First of all, I can't believe this thread has gone on so long.
Second, listen to Clarke. I've spent 20 years in construction and what he describes is the plan I came up with for my layout. Not that it is the only way to skin a cat, as selector and others have pointed out. But, what Clarke describes is the cheapest and easiest way to get it right.
I never did get the L-girder thing. To me it seemed like a massive waste of lumber and time.
I don't have a problem with anything else Clarke recommends, except the "Never" use "L" girder. Sectional boxed construction is actually a better choice for smaller layouts or a layout that may have to be disassembled someday.
Large layouts with 40-50' long peninsulas having curving and wandering facias, rounded peninsula ends with up to 60" radius are actually better built w/ "L" girder or any form similar. The "L" girder arrangement can change w/ the shape and angle of the plan. Rounded corners done with the crossmembers set on a radian allows for risers to be somewhat perpendicular to the tracks subroadbead.
The supporting members of the layout are positioned inboard from the facia allowing the legs to be positioned as not to cause tripping. Crossmembers can be cut to any shape the facia needs.
Track elevation are easily set and adjusted with the use of risers.
I find that in my opinion, The pros outweigh the cons with "L" girder for the massive layout we are building.
I did use 1X4 L-girders. I split ripped some of them in half down their lengths, and fashioned L-girders out of one of the 1X4's and one of their split halves across the top. What I didn't do was to then frame above them and add risers as some modellers seem to favour...takes up a lot of vertical space. What I did was to make a square frame of L-girders and add several joists across the long axis of the rectangles that the frames formed. Risers went to the joists as needed, and I think it turned out quite well.
Thank you for your professional insider's perspective about benchwork and platform tops. I do have one question(s) about your statement of "never use L-girder benchwork and do use very well supported sectional platforms"... Why and are you suggesting a "box like" or "multi-box like" sectional platform? What are your suggestions for section or box thickness? Suggested size of the boxes and sections? Are they squares or rectangles? Any other suggestions are greatly appreciated. And of course, I could go on ad nauseam Guess I better not! Thanks for jumping-in!
grayfox1119 wrote: Clarke, great technique and I totally agree with construction. We spend thousands of dollars, some even 10's of thousands of dollars on rolling stock, locomotives, scenery, etc, that is constantly expanding over time, but we can't spring for a few more bucks for 3/4" base plywood? You purchase the plywood once, spend the difference between 1/2" plywood and 3/4" plywood, and never have to worry about the base again. Yes, it is heavier, and some people say it is too heavy to handle a full sheet to cut. Every Home Depot or Lowes in our area make the cuts for free right at the store. So forget that argument. Good luck with your layout, send us some progress pictures when you have them...
Clarke, great technique and I totally agree with construction. We spend thousands of dollars, some even 10's of thousands of dollars on rolling stock, locomotives, scenery, etc, that is constantly expanding over time, but we can't spring for a few more bucks for 3/4" base plywood? You purchase the plywood once, spend the difference between 1/2" plywood and 3/4" plywood, and never have to worry about the base again.
Yes, it is heavier, and some people say it is too heavy to handle a full sheet to cut. Every Home Depot or Lowes in our area make the cuts for free right at the store. So forget that argument.
Good luck with your layout, send us some progress pictures when you have them...
I don't skimp on the benchwork, but I'm not going to waste my hard-earned bucks on unnecessarily heavy roadbed. Just a couple of sheets of 3/4" plywood and I've wasted more than enough extra cash to purchase a plastic car kit. Plus the thicker plywood makes clearance issues with lower level tracks more likely in areas where the clearance is tight already. No, I'll stick with properly-sized roadbed and buy the extra car kits.
We're currently working on our forty-ninth or fiftieth layout project, some of them as large as seven thousand square feet. Except in extreme circumstances, we have never used any plywood over one-half inch for platform tops or roadbed. If we have any "secrets" about how we do it they are very simple ones: never use L-girder benchwork and do use very well supported sectional platforms.
After using high quality dimensional lumber for framing for many years, we have switched to seven-ply three quarter inch plywood for framing and one-half inch for platform tops. Depending on the project we will use either a very well supported plywood cookie-cutter technique or foam trackbed raised on custom cut foam risers. Forget twenty inch support centers on cookie cutter construction, wood is cheap at any price---repairing a mistake isn't. The great thing about foam construction, besides it's stability (if properly installed), is that the world doesn't end at track level the way it does with a plywood surface. If you start with a plywood base topped with a two inch foam board these problems/worries practically vanish. If the landscpe we are modeling is mountianous we will move the platform base all the way down to the floor if necessary, but if that support platform isn't there all you have is a bunch of expensive spaghetti. There is also no law that says you can't mix the two techniques, using internal wood bracing to solidify foam costruction. Some of our larger projects have had vertical track separations of as much as five feet requiring a well supported elevated plywood trackboard skeleton to which sheet foam is attached and then liqiud two-part styrofoam is sprayed. But at the bottom of it all is the same thing---a very well built plywood platform.