Benchwork started

Of the many challenges that I anticipate to be a part of building a model railway in our living room, I need to find ways to make construction appear to move more quickly than it might appear it is. In short, prepare and pre-build as much as possible so when it gets to the site things happen quickly. Sometimes I think the best way to achieve this will be to build the layout in reverse (e.g. build the structures, build the track, build the benchwork, etc. in that order).

I prefer the use of plywood over dimensional lumber for the construction of model railway benchwork and have been wanting to try making up some of these laminated structural members described in Barry Norman’s book and also as Maurice Hopper used on his Stroudley Green layout mentioned earlier.
benchworksections
I already had some 3/8″ plywood on hand so made mine up using that. Basically, rip the sheet into 3″ wide strips and then laminate them together, spaced with blocks, into the layers as drawn above. I had enough material to make up three full lengths, four feet long. My layout is actually supposed to be five feet long so I wound up splicing in another length to bring each to that final length. Here’s a hasty photo of where I’m at right now.
DSC09912
This is really using plywood to it’s advantage and the resulting sections are strong and don’t flex easily yet still reasonably light in weight. I expect joinery will be mostly butting corners together and glue with screws. The contrasting grain directions should give the screws that much more purchase and, by design, I don’t expect the lumber to be prone to split. As great as they are, they look terrible but I expect to surround the finished layout with something that results in a much more finished appearance so this rugged looking plywood is hidden from view.

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2 comments

  1. Nice work, Chris.

    Barry developed that concept when he was building Petherick, as a better system than using dimensional lumber for an “open frame” baseboard where there would be scenery above and below the track.

    If you are working with a flat top baseboard, then a single 3″ wide strip of 3/8″ ply around the edges, with cross bracing and diagonal struts (these can all be made of much lighter material – 4mm (5/32″) ply has been successfully used over here) affixed to the underside of the surface, will be more than sufficient.

    I built some boards some years ago, 29″ wide x 48″ long, with this simpler construction. They had 4″ deep sides and ends made of 3/8″ ply, a 2″ deep longitudinal strut down the middle, also from 3/8″ ply, and an assortment of 2″ wide pieces of 1/4″ ply providing some cross bracing and diagonal stiffeners. These were all fixed to a 1/4″ top” in the case of the 3/8″ pieces, with screws and wood glue, but in the case of the 1/4 pieces, with wood glue whilst the board was inverted, with a few books here and there to apply a little pressure whilst the glue set. It is important that the 1/4″ pieces are a tight fit. I put a couple of cross pieces, about 14″ wide, on each side of the centre strut, let the glue dry hard, then put a total of 6 diagonal pieces into the resulting rectangles. On another board, I had two 3/8″ x 2″ longitudinals, about 12″ apart, to create an area down the middle which was free of bracing, as a lot of turnouts were going to appear above this. Finally, a third board had the sides reduced by about 1.5″, to raise the track bed up above the surrounding land. Here, there was a longitudinal piece along each edge of the trackbed (which was down to 2 tracks for half of its length) and once the glue had set here, 1/4″ ply was attached underneath the longitudinals, leaving the track clear but reaching out to the framing. 2″ deep pieces of 1/4″ ply were contoured and added on top, to provide the necessary bracing, etc.

    They were perfectly robust and strong. Barry Norman actually put one on the floor, and stood on the end piece whilst trying to twist the other end, 4′ above (and therefore almost at his eye-level*): he was impressed with the rigidity.

    Trevor Nunn has simply used 5/32″ ply for everything, with a similar approach to triangulation and bracing, on East Lynn and Nunnstanton, with 3″ deep sides and ends and 2″ deep bracing. (Unlike me, he was not trying to accommodate folding legs into his frames, hence 3″ was enough. Unlike me, he had faith in modern glues, and didn’t chicken out and use 3/8″ around the sides and ends!) If you have access to copies of MRJ, there was a good underside shot of one of East Lynn’s boards in issue 86. (I got a mention in that article, although not by name…)

    It all depends on what you are trying to achieve, but Maurice admitted to me that the boards on Stroudley Green were “probably over-engineered” (but done oh-so nicely).

    Hope that helps.

    Simon
    * Barry is actually taller than this, but he would think me an on-line impostor if I was not rude about his stature. I am not alone in doing this, I hasten to add.

    1. Good morning, Simon.

      Those two lengths of framing were just something I wanted to try and make up. I had a sheet of 3/8″ thick plywood in the workshop and was really fascinated with this idea – I just had to try it out for myself. They were simple to construct and are very strong as I expected they would be. To clean them up a little I expect to run them through the saw one more time to tidy up the edges and I’ll likely sand the faces to tidy them up too. Not that you’d see them under the layout but more to finish this example nicely. For a small layout as I’m proposing, I agree, there is no doubt that they are way too much for such a simple application.

      In a more practical application baseboard design and construction should be treated the same way we’d approach any construction project and perhaps we need to incorporate these decisions into the first days when the layout is still only living on paper. I think we spend a lot of time drawing track on paper and perhaps should be spending as much time on that same sheet developing the rest of the scene and then using that, more complete, plan to guide our framing ideas. I’ve spent a lot of time designing and engineering cabinetry, professionally, and sometimes I think someone should consider publishing something for the model railway market that showcases framing from the cabinetmaker’s sketchbook.

      We know that 1/2″ plywood can span 24″ on it’s own with no additional framing to help it “stay straight”. Typically, those same shelves run about a foot wide. Once we go past that two foot length the shelf should have a simple frame added around it’s perimeter. In it’s most elemental form, this frame can be 1/2″ thick lumber glued and screwed in place. The shelf and it’s frame will not warp and would be fine. Make this frame around three inches in height (1/2″ x 3″ x length of shelf) and you should be fine to approach four feet. Mind you as you approach four foot and longer lengths you need to start to plan for the shelf when it starts to bow. As the collapses down, under load, that frame around the perimeter will begin to splay outward and that’s why we add in the cross-members to tie those sides back to each other. We often use dimensional lumber here but a length of threaded rod would work just fine here too with a washer and nut outside each one. All of this assumes the shelf is supported by it’s legs also at the shelf ends and for shelves four feet or longer I’d strongly recommend moving those legs in toward the centre and placing them inboard a distance of one quarter the length of the shelf (e.g. a four foot shelf is divided into four, equal, one foot lengths and those legs should sit inboard one foot from each end. On a five foot shelf: 60″ divided by four equals fifteen inches and it’s this distance in from each end and so forth).

      So what would I actually prefer to try for my own layout. I could actually use those two lengths of Norman-esque frames and they’d be indestructible. Of that, there’s no doubt in my mind. I’ve been thinking about a simple frame made using three or four inch strips of 1/8″ “door skin” plywood. To keep this straight I figured I’d reinforce it with 3/4″ square blocking and cross-members at twelve inch centres. To provide somewhere to screw into I’d add more of that same 3/4″ as needed. Again, glue for the strength and screws really only for temporary clamping strength until the glue sets and only in those locations where I couldn’t just clamp it.

      For the top, 1″ thick rigid extruded foam would be lightweight and more than strong enough. I’ve used foam on a lot of layouts and it’s been terrific. That said, from the perspective of developing the scene it is no improvement over the 3/4″ thick plywood prairie it supercedes. While we don’t use as many oil-based glues and paints as we used to in layout construction, I feel it’s a pain to have to always be worrying about melting the foam when building the layout. I’d like to get back into a wooden deck for this next layout. I also prefer building up track over wood compared to foam – not sure why exactly, I just do.

      The three micro layouts I built this year were all built over frames made entirely from 3/16″ thick foam core. This material was fun to work with and building up the frames was very quick. The resulting frames were very durable and I can’t imagine a frame more lightweight. I enjoyed this novel alternative but, again, think I want to return to wood for the actual layout.

      I really appreciate your comments and enjoy the consideration. As I’ve been commenting, I enjoy layout planning, theory and design almost more than any other aspect of model railways so it’s component parts are always something I look forward to discussing. Thanks for taking the time to write back. I appreciate it.

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