Spokane International Railway is built using aluminum benchwork construction methods found on The Clinchfield Railroad in N Scale. The layout frame is constructed of three inch aluminum architectural channel. The frame size closely follows The Clinchfield Railroad plan,
which was designed by the late Gordon Odegard for Model Railroader back in 1978. I made some changes to The Clinchfield design by welding all the corners and cross members. This gave each section a rigid frame with very little effort. There are four frame sections. Two 36" x 72" self supporting tables with folding legs and two 23"x 84" bridge sections that interlock into the channel of the two table sections. This makes the foot print of the layout 6ft x 13ft. Unlike The Clinchfield, each table section is sheathed with 1/4" oak plywood. The 1/4" ply is the only wood that supports the foam scenery. All the track is laid on cork glued to the styrofoam sub-roadbed. This is what it looks like in its beginning stages. 
Each bridge section is C-clamped to a table on either end. Different thicknesses of extruded Styrofoam are glued together to change the elevation of the scenery and mainline. Making the layout portable means making it light weight. Each section is designed to be handled by one or two people. The Clinchfield design was one of the best N scale portable railroads built for display as well as portability. I wanted to take the layout design to the next level by using the new products available to today's modelers. To find out more about the construction, start at the July/Aug 2007 issue of N scale Railroading magazine.
