I have made some significant progress over the last several weeks.

Perimeter Benchwork supports: 
 I have seen several layouts with the benchwork cantilevered from the walls.   I like the open feeling it gives the floor and allows  maximum storage flexibility under the layout, which was a must.  Originally I had planned to use L girders on the walls with an L girder cantilevered out.  I helped a friend install his supports that did not use L-girders, so that convinced me to use a modified version of his method.  The benchwork has 4 main parts, a wall bracket, the horizontal joist, an angle brace and a splice plate.  For mine, I used a 24" long piece of 1x4 as a  wall bracket.  It could have been a few inches shorter but that didn't buy me an extra piece on a common length of lumber so I went with 24".  The joist is the depth of the benchwork, which varies from 16" to 30".  Downtown Wilmington (south wall) was 30", Wilmington Yard (west wall) was 27" and the north wall was a combination of 24 and 30" lengths.

The angled brace is cut at a 45 degree angle at each end  I originally planned to alternate 24" and 18" brackets, the 18" brackets would clear the book cases and the 24" would fit between them.  After working on the south wall, I felt that the 18" braces were sturdy enough and I could go all 18" braces.  The splice plate is 1/4" plywood cut into 3.5x7" pieces.

I located the studs on the walls with a stud finder and marked their location with chalk.  That makes it easy to wash off the marks later on if desired.  I located the top of the wall brackets on each wall and snapped a chalk line on the wall.  The brackets were screwed to the wall at each stud using 2" bugle head screws (dry wall screws), with the top even with the chalk line and the bracket vertical (checked with a level).   At wall outlets the bracket had to be raised up about 1-2" to clear the outlet (since they are also attached to the studs).   I then snapped a chalk line 1" down on the brackets.  I decided to attach the joists an inch down to lessen the chance that the bracket would split when the joist was screwed into the edge of the bracket.

The braces were pre-assembled by attaching the splice plate to the end of the brace.  All of the pilot holes in the joists and braces for attachment to the brackets were pre-drilled.  Assembly involved attaching the joist to the side of the bracket with one 2" screw.  The brace was put in position and the joist checked for level.  Then one 2" screw was put in the brace at the bottom to attach it to the bracket.  The joist was checked for level and the splice plate was screwed to the joist (since the splice plate was 1/4" ply, I used 3/4" screws).  Finally the remaining 2" screws were driven into the joist and brace to secure them.

This produced a very sturdy benchwork support.  The limitation of this design is that the supports are dependent on the wall stud spacing, so there is less flexibility of joist location.  Depending on whether you have 16' or 24" stud spacing in the wall, that could be a factor in the length of the span between supports.  Worst case scenario is if I needed some odd spacing, I could attach a 1x flat across the tops of the  joists and have a de facto  L girder to have a custom joist spacing.

Peninsula construction:
I recycled the old "blob", peninsula end with a turn back loop, from my previous layout.   The old blob consisted of two 4-5 ft. long pieces of L girder with joists attached to the top.  I positioned it in its future location on 4 legs (2 permanent and 2 temporary).  A short piece of L girder was attached under the ends of the joists where the peninsula would attach to the wall.  Two legs were attached to the L girder spaced 3 ft. apart to match the L girder spacing on the blob.  I then built to L girders to bridge between the legs and the existing blob L girders.  Once the new L girders were spliced in place, legs were permanently attached under L girder at nominally 6 ft spacing.  Joists were screwed to the tops of the L girders to tie it together.  Since the peninsula was going to have a lower level switching area representing a branch on it, it was built  approximately 6 inches below the perimeter benchwork.

Backdrop:
1/8" hardboard was attached directly to the wall using a brad nailer.  The seams and nail holes were patched and sanded and the backdrop was painted with two coats of Walmart "Blue Sky" flat latex paint.  (Aside:  If you drop a gallon can of  Walmart paint down a flight of stairs, the lid will come off the can.  Don't ask how I know.)  Light switches are normally placed about 48" off the floor.  Since I knew that would be right about the height of the layout and I knew that area near the door would be valuable real estate, I had them move the layout room switches up about 6 inches.  I cut a hole for the switch box in the back drop then put a 1/8" spacer under the switch mounting tabs to bring the switches and cover plate back up flush with the backdrop.

Design:
The basic design is an evolution from my previous layout, the classification yard will be recycled into the new layout.  I had hoped to recycle more but it is not looking as favorably on the other sections of the old layout that were salvaged.  Most of them will have the switches, rails and spikes reuse, but the roadbed will probably not make the transition to the new footprint.

Most of the design was done by sketching on odd bits of paper over the course of the last year or so.  Since the layout was in a similar length space, just wider, and the concept was retained, the design was pretty easy to replicate.  I don't have a single scale drawing of the layout and or actually of any piece of the layout.  That has saved a lot of time, but is a real bummer when it comes to sharing the design, especially in print.  I have had a couple inquiries about writing an article about the layout, but I don't really have any dimensioned plans of either my previous layout or this one.

 
I am a big fan of full scale planning.  After I put the benchwork in place I cut up some old mattress boxes (one benefit of moving is you end up with a lot of cardboard at your disposal) in the shape of the benchwork and then with photocopies of switches and chalk, started sketching out potential track plans. The Delaware River Extension (DRE) was pretty straight forward, but the downtown Wilmington area was harder to visualize.  When I cut the plywood for the subroadbed, I dug out my collection of buildings from the old layout and started playing around with them.  Add in some sticks of flex track and the switch templates and pretty soon I had a decent design.

There are four main areas I wanted to cover in the downtown Wilmington area.  The DRE was pretty easy, a lead along the back drop, hidden by foreground buildings, that pops out into its own switching area.  The other three were the King St Branch, the Maryland Ave Branch and engine terminal.  On the prototype the order  from "back to front" would have been the King St Branch, the Maryland Ave. Branch and the Engine terminal.   The King St Branch had the H&H shipyard along it, plus several smaller industries and the passenger depot at the end.  The Maryland Ave Branch had  the freight house, team track, a lumber yard  and a leather works.  Early attempts at a design tried to preserve that order.  I had the King St Branch towards the back or middle with the freight house and team track next to the aisle.  It just wasn't working.  The break through came when I mixed thing up a bit and moved the King St Branch towards the front, put the freight house and team track in the middle, on the other side of the lead itself.  If I considered the way the freight and passenger trains operated, it didn't change too much from the prototype, preserved the concept of two switching areas on separate leads and improved the access to the roundhouse.  I can live with that compromise.  There was one industry (a lumber yard) that got crowded out of the mix but I was able to expand H&H to include a lumber shed, so net-net, I still have loads of lumber consumed in Wilmington.

Risers:
I have cut about 60 1x4 risers to elevate the subroadbed above the joists.  Over the course of the next week, I will pre-drill the pilot holes and add some cleats in preparation for installing the risers.  Installing the old layout sections may be delayed a week or two while I build/rebuild a spray booth for the workshop.