The baseboard for "Shelf Island" is a small-scale version of traditional L girder construction. The layout is my first L girder baseboard and I think this is the easiest way to build a baseboard from wood - you build up the two L girders, put the cross members on top of them, and then add supports for the road bed. If you use fairly thin wood (mine is all a nominal 10.5 mm thick) you can pull it straight or curve it as you go along. Most of the joints are pinned and glued - I used veneer pins, these are thinner than panel pins and less likely to split the wood. I used wood screws where I needed the fixing to clamp the joint together while the glue set.
I drew the layout plan in AnyRail and used this as the construction drawing. The plan includes some lines and boxes to represent the structural parts of the baseboard, but I still ended up with the tie bar of one point plumb over a length of baseboard bracing.
I would happily upload the source file too but the blog editor won't let me do this.
I made the L girders themselves from lengths of pine stripwood, 45 x 10.5 mm vertically and 34 x 10.5 mm on the tops. This gives much the same cross-sectional area of material as a length of 2x1 PAR, but with probably twice the strength. The cross members are offcuts of the same pieces of stripwood, and these are on top of the L girders. I fixed the cross members at various different angles to help stop the frame from twisting.
The pine is hugely easier to work than the usual DIY-grade spruce and to be honest having finished the baseboard using pine, I took all my spruce offcuts (saved up over many years!) to the dump. Small baseboards don't need much wood and the extra cost of the pine is well worth the extra.
The track base is supported on 10.5 x 10.5 mm strips of pine and most of these are fixed at an angle too. The gradients are at a vertical angle (of course), and the bracing effect of all these angled parts combines to make a very strong frame. I have tried jamming one end of the layout against the bottom of a brick wall and I cannot twist the other end.
There is a diagonal under the right-hand end. I'm not sure if this was really necessary, but it was one of the first pieces I put in. This next photo shows the two L girders quite well. The edge with the two dowel sockets nearest the camera is two layers of wood glued together:
The road bed is 3 mm thick cork strips (Carr's) on top of 5 mm foam board. The foam board is the black, higher density version by Westfoam. I got all of the road beds out of two A1 size sheets of foam board, with one mistake thrown away and no useful offcuts at all. I laid the hidden track first - this is Peco Setrack number 2 radius, and a Setrack point:
The fiddle yard connects here in two ways, to make a long narrow layout or an L shape.
Most of my inspiration for this construction is from the book Miniature Landscape Modelling by the late John Ahern. Ahern did not write about L girders (he used lengths of plain wood instead) but the rest of the ideas are all there, in a book first published in 1954. I wonder what he would have thought of foam board - vastly easier to use than plywood. Here is a view a typical arrangement underneath the track bed:
I want to use the layout in a domestic setting and I have made the visible front edge as thin as I can - a length of aluminium angle. In a way, this makes for a third L girder. I bent the left hand end about 45 degrees so it does not catch in clothing when people walk past it.
This photo also shows where a length of 10.5 mm square stripwood curves downwards from a 45 mm cross piece to a 34 mm cross piece. This is one length of wood from one end of the layout to the other, This sort of approach helps to make the ends of gradients more gentle, and adds some strength to the framework too.
The right-hand end of the model will have a short narrow gauge tramway. The baseboard structure for this is more 10.5 x 10.5 mm pine stripwood, but built up from the structure for the existing road beds below rather than the L girders. This is an attempt to minimise the weight of the layout:
The road bed for the tramway is 3 mm foam board without cork underlay. The reason for this was to let me line everything up for a flat crossing of the standard and narrow gauge lines. It also let me curve the road bed downwards, to let the tramway run over a road bridge, and upwards, to improve the look of the model above the tunnel:
So far I have managed to avoid fixing anything to the vertical parts of the L girders, and nothing in the space between them. The idea is to be able to add some hinged legs which fold up underneath the baseboard. I might do this at the end of the project - it is easier at the moment with a trestle table for model making:
There are two plywood end panels on the baseboard most of the time now, these are fixed in place with wood screws. The panels let me turn the model upside down to work on the wiring and so on. Also, the trestle table is not quite flat so they let the model stand the right way up without rocking.
(first published 8 April 2015; edited 18 May to add details of narrow gauge tramway)