Modeling Information
There are two types of layouts, 
movable and immovable. Having been in the military for 14 years and 
moved some 8 times in those 14 years, I opted for a movable type of 
layout. I've moved it three times in the next 20 years as a civilian. 
There are two types of movable layouts: modular and sectional. 
Modular Type A.
 By definition,  a module is a section of benchwork and roadbed that is 
built to  common standard determined by the organization establishing 
the standard. Modules fit together with standard track connections at 
the ends, but builders can construct any kind of scene on a given 
module. - as long as one module fits against another module railwise. 
Modelers are generally confined to fixed-length modules of 4, 6, or 8 
feet long.
Ntrak
 is one of the modeling organizations that has created a commond 
standard and other modeling groups have developed standards of their 
own. Those layouts you see at train shows and flea markets are modular 
type A layouts. 
Modular Type B. Another group that does modular but differently is Fre-mo. Free-mo was developed with the idea that allows the modeler’s 
creativity to shine through their modules.   The Free-mo standard 
focuses 
mainly on the module end plates. The Free-mo mainline is centered on a two foot end so modules can be 
inverted 180 degrees and still mate up to the adjacent module without 
modification to wiring or track. This allows modeling of prototype 
track plans and operations in a modular environment. The length and track
 configuration of a Free-mo module or module set is up to the modeler as long as the module end plate standard is followed. . 
Sectional.
 Sectional design assumes that the layout is going to be moved at some 
point. Unlike modules, the sectional layout does not follow any standard
 track pattern because the pieces need to fit together only one way. The
 scenery can maintain continuity from section to section following the 
theme of your railroad. 
Benchwork
 is the same, the only difference is the connection points are designed 
with a move in mind. Assuming you don’t have to take your show on the 
road very often, you don’t even have to leave breaks in the track and 
scenery at section joints. When it’s time to move, simply cut the rails 
and slice through the terrain. As long as you have some extra track and 
scenery materials on hand, you’ll be able to “heal” the scars at the 
section joints 
Dominos. David
 Barrow devised a sectional construction system using 
standardized rectangular layout segments (think table layout that disassembles). He likes to lay out track plans
 by fitting these sections together end to end and forming 90-degree 
corners, so the comparison to the game of dominoes was obvious. He’s  
described his domino method in both Model Railroader and Model Railroad 
Planning articles. The illustration shows the basic form of domino layout
 sections. 
The WWSL
WWSL ver. 2.0 was several concepts wrapped up in one. I wanted modular 
construction that would be easy to move . I was taken with the idea 
presented by David Barrows about 'domino's. His choices for his layout 
was:
- Segmental benchwork construction.
 - Minimalist design aesthetics rather than a realistic scenicked railroad.
 - Wide aisles.
 - Finished open room with carpeted floor.
 - Off-the-shelf
 unpainted code 100 flex track and no. 6 turnouts operatied by manual 
ground throws to minimize wiring and complexity. 
 
This 
made a lot of sense to me - after all all my layouts to date had 
essentially been minimalist designs rather than realistic scenicked 
railroads. Heck, I hadn't even painted the plywood green!
This 
minimalist idea was followed by Tony Koesters Layout Design Elements That allowed
 me the opportunity to develop a model railroad focused on operations 
with an ability to change the layout based on my change of operational 
preferences. I always enjoyed switching, and car movement, mainline 
operations as shown in the model railroading magazines of the time less 
so. I did enjoy the freedom to build a multi-track coal mine with empty 
and load yards, and then months later change those LDEs to reflect a 
grain elevator and its similar but also unique requirements. Wetting 
down and removing the white glue'd down flex track and re-configuring the industrial 
spurs was a way of continuing the hobby as I enjoyed it. 
The WWSL vers. 2.0 domino. While David Barrow's dominos used plywood as its subroadbed/roadbed, I
 knew at some point I would decide to do a WWSL vers 2.0 which would 
entail scenery, etc.  Mounting a plywood base directly on 
the bench work gives you ZERO opportunity to work in any downward verticle scenery. I saw styrofoam and the 2" x 2s as a way of allowing the vers 2.0 the option of having some  features such as roadbed slopes, small streams, culverts, bridges, etc.  
The
 requirements of the military move didn't support the idea of L-girder 
benchwork, so my modules were constructed so that when it came time to 
move all i needed to do was disassemble them into the core 2 foot x 8 
foot sections and then surround them with 1/4 inch plywood to avoid the inevitable move damage. 
The section was essentially a two inch piece of styrofoam glued to a 1/8th 
inch of masonite with wood  glue. A twenty four inch 2" x 2" piece of 
lumber was screwed and glued into the masonite panel and was then 
screwed onto an L-girder made up of a 1"x 2" and 1" x 4" lumber. 2" x 2"
 legs were bolted to the L-girder ala Lynn Wescott.
In this case, the styrofoam, the masonite, the 2" x 2"s and the 1"x3" gives approximately 4 inches of downward
 dropping scenery potential. 
The WWSL vers.3.0 
The
 WWSL vers. 2.0 was single decked for a number of years. I found that 
the second level was difficult if not impossible to install with the 
L-girder in place. When I started the benchwork for WWSL vers 3.0 I 
removed the Lgirders and installed a horizontal 1"x3" in its place - to 
add vertical stiffening to the section. This is what the vers 3 module 
looks like. 
I'm recycling 16 WWSL 2.0 sections to the new version. I've found those sections much easier to built, carry and install on the layout.  
See 3.9 Module / Section Construction for construction details.