You can tell I'm on a roll, I've posted for three straight days. Having this being the 3rd rebuild (and enlargement), I'm getting very good at it. I don't have to think a whole lot about how to joint part A to part B, or what's the best way to join girders meeting at 90º, I just do it.
I remeasured and reset the positioning on the 2nd (main) module on the floor using the back wall as a datum and double-checking against a chalk line (without the chalk). The offset was supposed to be about 23" and it's within the margin of error for that. Once I got the offset where I wanted, I went back and added the 2nd set of splice plates to lock those bends in that position. While doing this, I got the saber saw and sliced off the offending diagonal braces that were sticking up above the girders.
I then set up the longitudinal positioning by taking a reference point from the left end of the wall girder and the end point of the main module's left end. The main module is to extend past the wall girder by 2'-6". I used a 1 X 3 with line at that distance clamped to the wall girder and the inner girder of the end unit (3rd module). Again used the chalk line to get the distance right. The layout is still light enough so with a good tug I could pull the entire main module towards the left without assistance.
Now it was time to build the 3rd module which comprises the layout's left end. I needed two leg sets that had a 2'-6" separation distance (it's a coincidence that it's the same dimensional as the left end offset), so I took another set of legs from the previous layout and adjusted them. Since this distance wasn't so much larger than the previous version, I was able to simply remove screws from the diagonal braces—2 from one side and 1 from the other—swing the diagonal to a new position to meet the other leg, and then screw them down in the new position. I still use a spacing brace to hold the position as before.
The inner girder was already clamped into position on the end of the main module, so it was a snap to position the outer (and shorter) girder on the legs sets that I just built. The outer girder was to extend rearward from the inner girder by 3". I measured and marked this off on the outer girder and clamped the leg on that spot.
Here's the clamping scheme.
While I could have fastened the inner girder to the ends of the main module's girders by screwing into the end of these girders' 1X4, I don't like putting screws into end-grain unless I absolutely have to. It's just not as secure. Instead, I like to install a mounting block which is screwed into cross-grain and then use carriages bolts for added strength.
This was the outer edge. The inner girder connection is done the same way.
So here's the end module completed. I'm now working on the corners. The front left corner is going to have two small L-girders that will be interconnected on the bias. The rear left corner is much more complicated. It will have the girders drop down about 10". This will be the location of the layout's main bridges and the deep channel will be where the waterway will be. Of course I'll document this is agonizing detail.
Here's the whole deal as it appears so far.
Today was also a good day for my grandson, Alex. He officially finished his F-18E Super Hornet. It was an eight month project and it wasn't easy. It was completed over a lot of interruptions including school, camp and family vacations, but he didn't give up. He asked for help and got it when he needed it, but did almost all the assembly himself. He relied on me to manage the airbrush and to scratchbuild two missing parts. He was very proud of the accomplishment.
I just edited the detailed construction drawing to ensure that it matched the "as-built" structure that's going on in the basement. The joist layout is an approximation. I make joist assignments on the layout itself and I evaluate the stress points under each sub-roadbed panel. This is a PDF and I don't know if it will work. Can't hurt to try. It will help folks understand the geometry.
I take the track plan from RR-Track as a screen capture. Paste it into CorelPhotoPaint and then save it as a GIF file with a transparent background. I import this file into CorelDraw and enlarge it to the exact size of the layout as noted in RR Track. I can then overlay the track over the sub-roadbed panels and still see through it. If you keep it as a JPG or Bitmap, the background is opaque white and hides what's below it. It's how I design the sub-roadbed panels with confidence that the track plan will fit as designed. It works! You can also do these same steps (with slight differences) in Adobe Illustrator and PhotoShop. I have both products loaded on my laptop, but am more familiar with Corel products so I default to them.