Construction of the Helix Begins

My main task for the Christmas-New Year's week was to begin construction of the helix at the center of my layout (see Track Plan). Completion of the helix will allow for continuous operation. The two-turn, double-tracked helix also serves as serial staging and will hold (2) 25 car trains in each direction. I've set myself the task of completing the helix and at least one track on it by April 2012.

I had designed and ordered a template to cut the sectors of the subroadbed and lay out the center lines of the two tracks (see Track Templates), but the benchwork to support the subroadbed had not yet been designed. I used TurboCad 14 Delux to design the benchwork for the helix.



The octagonal benchwork is made up of 8 trapezoids 44.25 x 58.25 x 18.75 on the short side. The two concentric circles indicate the subroadbed. Radii on the helix are 66.5 inches and 62 inches. The benchwork is 141 inches across - this is some helix!

Here I'm using the helix template to mark out the subroadbed prior to cutting.



I do my cutting outside, wherever possible. Here are 9 sectors of subroadbed, the yield of one sheet of 3/4 inch plywood.





The photo above shows the decks of the first four sections of the helix benchwork completed. The following photo shows the first three sections of benchwork assembled as a test. These sections are not in their final position.



The benchwork is 54 inches to the top. My current thinking is that only every other section will have legs; alternate sections will be suspended between the sections with legs. Squaring-up and leveling the benchwork may be difficult with this arrangement; if so, I will have to attach legs to each section so they can be leveled separately.