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"L" Girders in Benchwork

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"L" Girders in Benchwork
Posted by RicZ on Monday, September 5, 2011 5:20 PM

What was the purpose of the "L" girders in benchwork?  Was it designed for strength to support the heavy placer scenes or was there another purpose.?  I have been using box frames made from 1X4s in the past.

Ric

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Posted by cuyama on Monday, September 5, 2011 5:44 PM

RicZ

What was the purpose of the "L" girders in benchwork?  Was it designed for strength to support the heavy placer scenes or was there another purpose.?  

L-girder might use a bit less wood and certainly requires much less precision in cutting.

Most importantly (I think), it allows one to move the joists around a bit as needed to accommodate scenery elements and subroadbed risers. Some folks also find it easier to build benchwork with curved edges using L-girder.

It works great, as does grid-style.

For a detailed explanation of the strengths and weaknesses of various benchwork techniques, Jeff Wilson's book Basic Model Railroad Benchwork: The Complete Photo Guide is a good source.

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Posted by gandydancer19 on Monday, September 5, 2011 5:49 PM

On top of the L girders were fastened cross joists.  Then risers were fastened on the joists.  As the sub-roadbed was being installed and fastened on the risers, you may find some areas where an upper track support would be in the way of a lower track.

By using the L girder method, moving a joist and/or the risers after they were installed was easy because it is all open during constriction, and everything was fastened with screws and not glued.  (The two pieces that made up each L girder was glued if desired.)

This type of benchwork is extremely strong.  Also, this type of benchwork was designed way before building foam became popular.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

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Posted by wp8thsub on Monday, September 5, 2011 11:49 PM

As I understand it, L-girder was developed for two purposes.  One, in an era before seemingly everybody had access to a power chop saw, it required no precise cuts.  Two, it allowed for ready access to fasteners from below, which satisftied former MR editor and L-girder proponent Linn Westcott's fanaticism about such things.

I've used both L-girder and plain open grid, and find L-girder a bit weaker, as well as somewhat more costly in materials and labor to build.  It also is thicker than open grid, and as such is less useful for multi-deck layouts.  It still has plenty of adherents based on its original strengths.

Rob Spangler

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Posted by fwright on Tuesday, September 6, 2011 1:02 AM

wp8thsub

As I understand it, L-girder was developed for two purposes.  One, in an era before seemingly everybody had access to a power chop saw, it required no precise cuts.  Two, it allowed for ready access to fasteners from below, which satisftied former MR editor and L-girder proponent Linn Westcott's fanaticism about such things.

I've used both L-girder and plain open grid, and find L-girder a bit weaker, as well as somewhat more costly in materials and labor to build.  It also is thicker than open grid, and as such is less useful for multi-deck layouts.  It still has plenty of adherents based on its original strengths.

Like Rob, I have built both ways.  I found three other advantages to L-girder.  The L-girder itself is stronger than the same size 1x lumber, which allows a slightly longer distance between legs.  By the charts for minimum deflection under load, a 1x4 has a maximum span of 7.5 ft between supports (less than 8ft spread of legs).  Adding a 1x2 flange to the 1x4 takes the support span max to 13ft for the same allowable deflection.

In my repeated moves to different climates, warping of wood happens.  In a glued L-girder configuration, the two pieces of wood fight each other's tendency to warp, making for a more stable girder than straight 1x4 or 1x6.  This turned out to be L-girder's most valuable quality to me.  I will often use L-girder in box frame construction to prevent warping of the longitudinals or sagging of joists.

In L-girder, the joists are not supported at their very ends.  This allows for the less precise cuts, and use of smaller lumber for joists for a given deflection compared to end-supported joists.

Rob is right, the box grid with close fitting joints has less leverage to rack than the multilayer L-girder, and thus feels stronger.

I place more value on being able to easily change things than Rob does.  Therefore, all screws from below is more important to me than it is to him.

The extra thickness of the multilayer L-girder is a significant drawback in many situations - particularly moving, multi-deck, and shelf layouts.

Bottom line:  what are the most important features of benchwork to you?  Then choose accordingly.

my thoughts, your choices

Fred W

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Posted by Paulus Jas on Tuesday, September 6, 2011 1:30 AM

hi gentlemen,

one thing to mention at last. The L-girder system is not stable without diagonals. The beauty of the system is you don't need to add them. Strange as it may sound, it is the subroadbed attached to the risers that takes care of that.

Smile

Paul

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Posted by tomikawaTT on Tuesday, September 6, 2011 1:40 AM

The L girder configuration, with supports at the 1/5 and 4/5 length points, has two benefits which I don't find in box frame construction:

  1. The legs are well inside the fascia line, most unlikely to be kicked by operators or visitors.
  2. There are no load-bearing fasteners driven into the end grain of wood.

The one disadvantage is that L girder framing is thicker than box framing.

My own layout is framed in (mostly) L-girder fashion, but using steel studs instead of wood.  Here in the dessicated desert wood can, and does, assume wierd and (not so) wonderful shapes as it dries out.  Steel is unaffected by the lack of humidity.  Since I am, at best, an indifferent woodworker, steel is a better fit for my skill set.

Chuck (Modeling Central Japan in September, 1964)

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Posted by bogp40 on Tuesday, September 6, 2011 9:31 AM

The "L" girder method will also allow for greater spans between legs (providing that the appropriate size/ height is used) some have even fabricated the "truss" to span greater distances.

The ability to place risers on the L girder also allows to shape curvature and radius to the facia. Example would be to run angled L girder on a turn and to run the joists in a radian and curve the facia. This allows the risers to be closer to right angle to the track. Of coarse this can be done w/ boxed frame, but it is more work in cuts and fitting of the joists. Angled front facia on boxed frame requires support legs at each break.

Here is an old pic from the club that will show a variation of mixed L girder and boxed frame.

L girder will allow you to build scenes well below the track level, the L girder can be dropped to a lower height or just run taller risers.

Boxed frame is better for narrow bench/ shelf, modular or future dissassembly or for those building w/ flat base foam layouts.

 

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by wp8thsub on Tuesday, September 6, 2011 10:36 AM

fwright

I found three other advantages to L-girder... 

I place more value on being able to easily change things than Rob does.  Therefore, all screws from below is more important to me than it is to him....

Bottom line:  what are the most important features of benchwork to you?  Then choose accordingly.

Good points Fred.  Choose based on what's important to you.  You correctly assumed that fastener access from below isn't as important to me as some, although I usually build so I can get to just about anything from the side.

To add to what you said about reducing deflection and increasing span between supports, I sometimes use hybrid construction, adding a top flange to the side members of the benchwork grid so it essentially has an L-girder down both sides.  This gives me the best of both systems - the reduced tendency to rack afforded by "studwall" grid construction, plus the extra stiffness afforded by the flange.

Rob Spangler

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Posted by BATMAN on Wednesday, September 7, 2011 11:20 PM

I found the earlier comments about lack of access to power tools in the early days as being a reason why     L girder benchwork came about thought provoking.Hmm  I have seen a lot of older L girder layouts and most (not all) were just really lousy woodwork at best. Thinking back to the tools we had in our homes when we were kids as compared to today is another eye opener. An electric drill was about it for most of the homes back then. My Dad also had a skill saw and it was often borrowed by the neighbours.

I have a workshop full of power tools and the big box stores will cut anything you need cut if you don't. For that reason I think L girder is going the way of the Dodo. I looked long and hard at L girder before I started my current layout and to be perfectly honest I didn't see a reason why anyone would use it. Cutting sturdy joints on the saw takes seconds. My grid benchwork is all lap joints glued and screwed. It is lightweight and very strong. All my 1" x 4"s were notched on the radial arm saw in minutes. I can't imagine the hours of labour it would have taken doing something like that by hand.

We have evolved with technology and that includes basic construction techniques. I have used more than one method on my current layout and who knows someday I might find L girder just the ticket to an unusual situation.  I'll let you know.Smile

 

                                                                      BrentCowboy

Brent

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Posted by cuyama on Thursday, September 8, 2011 10:29 AM

BATMAN

 I think L girder is going the way of the Dodo. 

Seems unlikely. For people who are interested in curved benchwork edges, scenery well below track level, and minimal material overall, L-Girder still has benefits for many layouts.

For people who cover their entire benchwork surface with a monolithic sheet of foam or plywood, L-girder may seem less interesting. But I see many experienced layout builders (including those who've built more than one) still building L-girder, even with a shop full of power tools at hand. 

If you've never had the experience of  helping to fill a good-sized room with L-girder benchwork in a weekend, as I have, you may not fully appreciate how well it can work.

Grid is fine. L-girder is fine. Much more time is spent talking about and wringing hands over benchwork choice than is needed to build it, typically.

Byron

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Posted by rrinker on Thursday, September 8, 2011 11:20 AM

cuyama

Grid is fine. L-girder is fine. Much more time is spent talking about and wringing hands over benchwork choice than is needed to build it, typically.

Byron

Amen.  Each has its advantages and disadvantages, and it's all a matter of choice as to which advantages you need and which disadvantages you can work around to make your layout design a reality.

                           --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by BATMAN on Thursday, September 8, 2011 1:19 PM

Please don't take my comments on L girder as a rejection of that method. In the 60s and 70s Dad and I spent lots of time at MRR friends working on layout and they all used that method. That being said, in the last ten years after I got back into the hobby I have visited many home layouts and I have not seen one put together with that method.

I think one reason is we live in a more mobile society and a lot of people build a layout with a possible move in mind. Another is with a change in building codes windowless basements are also not available in newer houses. Layouts are built having to accommodate these things. People are getting more and more creative in there benchwork construction, be it in materials used or how it fits into the home as far as sharing space with the family.

I am firmly in the "there is more than one way to skin a cat camp" and I like to try new things. I will not argue about what method is better, as method is always a personal choice.

As I said before, Robs comment about peoples access to power tools and better equipped home workshops just got me thinking about why I see fewer layouts built with the the L girder method. I think it was an accurate statement that gave this history buff something else to ponder.

Instead of saying  L girder is going the way of the dodo, maybe I should have ask "why do you think fewer and fewer people seem to be using the L girder method"?  Or is that observation an anomaly?

 

                                                           Brent

 

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by cuyama on Thursday, September 8, 2011 1:36 PM

BATMAN
 "why do you think fewer and fewer people seem to be using the L girder method"?  Or is that observation an anomaly?

Still plenty using it in California (and among my clients, who are all over the world).

Again, there are lots of different techniques being used for benchwork today and nearly all work with different pluses and minuses. For example, we covered three lightweight methods based on either Gatorfoam(TM) or Luaun plywood in the the latest Layout Design Journal (#43).

I don't personally see a pressing need to make far-reaching pronouncements about benchwork. Just git 'er done!

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Posted by fwright on Thursday, September 8, 2011 2:17 PM

BATMAN

Please don't take my comments on L girder as a rejection of that method. In the 60s and 70s Dad and I spent lots of time at MRR friends working on layout and they all used that method. That being said, in the last ten years after I got back into the hobby I have visited many home layouts and I have not seen one put together with that method.

I think one reason is we live in a more mobile society and a lot of people build a layout with a possible move in mind. Another is with a change in building codes windowless basements are also not available in newer houses. Layouts are built having to accommodate these things. People are getting more and more creative in there benchwork construction, be it in materials used or how it fits into the home as far as sharing space with the family.

As I said before, Robs comment about peoples access to power tools and better equipped home workshops just got me thinking about why I see fewer layouts built with the the L girder method. I think it was an accurate statement that gave this history buff something else to ponder.

Instead of saying  L girder is going the way of the dodo, maybe I should have ask "why do you think fewer and fewer people seem to be using the L girder method"?  Or is that observation an anomaly?  

In the 1960s, when MR was pushing L-girder, it was used extensively in nearly all the project layouts of the period - regardless of whether L-girder was the most appropriate method.  IMHO, the poster child for needlessly over-complicating the benchwork to use L-girder was the Kennebec (sp?) Central in 1972.

The other side of pushing a particular method, technology, or set of materials is that beginners get the impression that the named method is the best method for their layout.  And since beginners build predominately closed-top layouts, L-girder was used by beginners for closed top layouts, where many of its advantages are lost.

In the 1980s and 1990s, L-girder started getting bad-mouthed as needlessly complicated - and it is for a 4x8 closed top layout.  Foam top benchwork has become the new darling method of the mr press, again regardless of its strengths and weaknesses for a given situation.  But I can easily see where most beginners would believe that closed-top foam benchwork is the universally best layout construction method today.

Another reason is that L-girder is not necessarily a great construction method for a shelf layout - in fact, much of the time it would probably be a poor choice.  But there are far more shelf layouts these days then were 30-50 years ago.

My conclusion is yes, fewer layouts are being built with L-girder than in the past.  But those model railroaders who are using L-girder are choosing it based on the method's merits for their situation rather than because somebody else says it's great.

just my thoughts

Fred W

 

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Posted by RicZ on Thursday, September 8, 2011 3:37 PM

Many thanks for your help.

Ric Z

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Posted by BATMAN on Thursday, September 8, 2011 3:45 PM

cuyama

I don't personally see a pressing need to make far-reaching pronouncements about benchwork. Just git 'er done!

Sorry Byron

I was not meaning to extoll one method over the other. I thought the conversation was more about where we've come from and where we are going as far construction methods. I have great conversations with friends in subjects like aerospace and medical breakthroughs even though I am at best a armchair participant.

Understanding why things are like they are through discussion is how we learn. Discussing and questioning things should not be construed as disagreeing. Critical thinking is how we improve things.

Perhaps this is the wrong place for this. I'll move on.

 

                                                                          BrentCowboy

Brent

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Posted by Paulus Jas on Friday, September 9, 2011 3:23 AM

Sorry Brent,

Yes indeed, armchair participants can often talk for ages. In my country we call them bedroom scientists or people not hindered by knowledge or just bar-talkers. (if you are old enough, MR had a bull-session in the past) This is not bad at all, having conversations is great; to call them critical because you or me are involved is a bridge to far.  Sometimes, when you are lucky, you'll encounter a professional, if he or she is a great teacher as well your or my horizon might be broadened.

To be more specific, if you look at construction sites, you will notice always L, T or U beams are used. A flat strip of wood or iron just sags. To place this knowledge in the "where we are going are where we are coming from" list is overkill.

Byron's opinion was pretty clear, so is mine. About 50 years ago i learned that often more scenery, on the shallow part of the real world we use to model, was below then was above the railroad-tracks. A flat-top does not seem to be  the best choice at once automatically . 

Keep smiling

Paul

 

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Posted by HaroldA on Friday, September 9, 2011 6:56 AM
For me, when I moved my layout from my previous house to this one (something I don't recommend by the way) everything pretty much remained intact. Any issues I did have were created by the movers. Then when I decided to move the sections to the basement, I removed the roadbed, numbered all the remaining pieces and resaasmbled everything almost without a problem. I attribute this to the L-girder construction. The one criticism I have of the system is that moving a joist to make modifications once roadbed is in place can become major surgery. Other than that, I have used the system for years and it's been great. Wasn't this one of Linn Wescott's 'inventions?'

There's never time to do it right, but always time to do it over.....

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Posted by papasmurf on Friday, September 9, 2011 9:15 AM

Being old geezer, yours truly read a LOT about L-girder benchwork ala Linn Wescott;  used it meself.. The one very nice feature of same: IF, while preparing to install subroadbed/ track [ or even long afterward, as many modelers did! ], you suddenly decide to put in a river or road,  the  front-to-back crossmembers could be installed at, say, a 45 degree angle [ or any other angle, to fit your l/o needs ], lower elevation road or waterway baseboard cut, installed and you're good to go with painting, terrain, scenicing. And many modelers would cut their fascia to expose that road or waterway's forward end, thus increasing the scenic impact of their layout for visitors.  my 2 cents.....papasmurf in NH

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Posted by IRONROOSTER on Friday, September 9, 2011 10:10 PM

You don't need a lot of power tools to build grid style benchwork.  Before I moved my power tools to my retirement house, I built a 5x12 open grid benchwork on wheels using a power drill, hand saw, miter box, clamps, and saw horses plus the usual miscellaneous hand tools such as tape measure, combination square, etc.

But it really doesn't matter which method you use, just do it correctly.

Enjoy

Paul

If you're having fun, you're doing it the right way.

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