This will be one very

This will be one very interesting thread to follow. Keep us posted.

I like how big your basement is and how the space allows a lot of room for photography.

"I am debating between making

  I tend to build benchwork in about 6 foot segments. I find 4 foot too short and 8 foot a bit harder to move. I don't use just one size sections though, I build them to fit the space and put the section joints in a spot where it will least disrupt the tracks when disassembling the sections( try to keep turnouts, buildings, etc. off the joints ) I would limit the removable section to about 30 inches to make it easier to handle,and would try to arrage the track plan to work as a point to point layout when the removable section is not installed......DaveB

Thanks for

Thanks for respoding  Deemiorgos and  ctxmf74 my next post will be the start of a blog.

I plan on taking lots of photos and videos of the entire process and once its up and running for sure.

The removable section will a single track on a plank of wood 24 inches or so long with walls either a bridge or tunnel for the pasenger train. The Freight Train will alway be point to point.

My old layout had 24 inch tall legs + casters, the new one will have 48 inch legs plus casters. The reason is my basement does get wet time time 1/4 inch puddle in a few spots and I want to move it if need be or as I finish the basement etc.

Thanks again for reading!

If you have easy acces to the

If you have easy acces to the outside, 2x8 would work just fine. 2x4 or 2x6 would be easier to move out of basement if  you ever decided to move.

Sizing - Do some simple sums

G'day Dan, 

While your stated intention is to have a sectional layout on casters that you can roll around to get at cellar walls etc later as required, remember that one of the advantages of a modular/sectional build methodology as outlined under TOMA principles, is the ability to do stuff like this to get at wiring etc in the construction phase.

Using lightweight construction techniques I can move and flip this  4'3" long module by myself. It weighs in at under 40lb fully sceniced. So I can work with a linear weight of about 10lb//' of modular length. If you have an additional person to help with this type of stuff, then that's good. But If you don't...

Now remember also I'm using these tables as layout support. I don't have heavy leg structures attached to the module frame and top. As stated, your aim is to be able to roll your modules on casters. This implies a reasonably heavy set of legs for rigidity and on which to mount the casters. So you will be unable to match my modular weight/' once the legs become semi-permanently attached to the module top and frame. So let's assume you permanently attach your legs after you have the track down and have any "flipping" necessary to attach wiring/point motors etc already done. Let's have a look at your basic module top and 4"x1" framing proposed in your original post. Here comes the sums...

For a 4' long module, assuming 1 transverse brace placed "centrally" (can be moved a few inches either way to dodge point motors etc)  Your real rigidity is in the 1/2" thick ply. top.

using the plywood weight calculator at   http://theplywood.com/weight and white/yellow pine ply 

1/2"plywood top - 4' by 2'  = 7 lb

Module framing  at 0.64lb//' from  https://www.engineeringtoolbox.com/structural-lumber-properties-d_1835.html

2 longitudinal stringers - 4' long x 4"x1" = 2 x 4 x 0.64 = 5.12 - call it 5lb

3 transverse stringers- 2' long x 4'" x1" =  3 x 2 x 0,64 = 3.94lb - call it 4lb

Total module weight = 16lb for a bare module top

For a 8' long module assuming 1 transverse brace placed every 2' (can be moved a few inches to dodge point motors, etc) 

Using 2 4' by 2' 1/2 tops = 2 X 7 - 14lb

2 longitudinal stringers - 8' long x 4"x 1" = 2 x 8 x 0.64 = 10.24lb  call it 10lb

5 transverse stringers - 2' long x 4'" x1" =  5 x 2 x 0,64 = 6.4lb - call it 7lb

Total module weight = 31lb for a bare module top

You'd want to have 2  persons available to flip ths 8' long module for wiring work at a bench, Realistically you are looking at about 5/lb for each foot of module without including the weight of any support structure, track or scenery. Any of these can rapidly add weight to a module. I'd be recommending shorter modules just based on these basic sums. Even with 4' modules, if there is any lifting or flipping to be done rather than rolling, I'd be getting a second person to assist.  

I can just move my 40 lb 4'3" x 2' module by myself if I have to lift it rather than skid it from one table to another. Please have a look at my responses on Page 2 and 3 at  https://forum.mrhmag.com/post/toma-ideas-in-practice-12207107  especially at the "awkwardness factor",  There is also some other stuff in that thread that might be relevant for you,

Lots to think about! I do

Look at painting the walls

Look at painting the walls with Drylok masonary paint. It will cut down on lots of dust and dirt and be fairly cheap. For a low cost ceiling 5 mm underlayment plywood will be cheap and keep dust and dirt from th joists off the layout. Paint it white and you will feel like you added several lights as the reflected light will be very helpful. Both are very low cost when you do them yourself.

2x4 vs 2x8

A lot of it depends on why you are building a sectional layout.  

Are you building sections because you think you will move?

Are you building sections because you want to rearrange the layout?

Are you building sections because you want to swap out sections?

Are you building sections because you want to remove pieces and work on the work bench?

Are you building sections to force yourself to build incrementally?

Are you building sections because its "trendy"?

Shorter sections mean more joints between sections.  Think of it this way, do you use sectional track or flex track?  Same concept with module length, more joints mean more electrical connections and more physical connections.

With shorter sections you have to consider the joints in relation to the track, the scenery, the buildings.  Putting a complicated junction with lots of switches and tracks over a joint, means if you split it, there is a lot more work to disassemble it and even more work to try and put it back together, there are not only the track alignment considerations but electrical feeders and operating linkages.    Having a joint in the middle of a wooded area is pretty easy to conceal, having a joint through a river or on a prominent rack face is harder to disguise.

Shortere sections generally mean more legs with makes under layout storage and access more problematic.

Longer sections are harder to move and a lot heavier.  They are more cumbersone to fit through doors and around corners in stair wells.

Longer sections are less flexible to reconfigure and fit into a different space, especially a differently shaped space.

My previous 3 layouts were sectional layouts built on what started out as 30" x 72" sections.  I had such bad luck trying to reconfigure them every time I moved, I basically rebuilt them every time.  There really wasn't any advantage to the building sections for my situation.  As a result, my current layout isn't sectional.

I am building sections

I am building sections becuase:

1) It forces me to build incrementally. See my original post after 15 months I had a layout (100 real feet of track) that wasn't wired. I feel buiding 1 or 2 2ftx4ft sections at a time will let me play with the trains faster.

2) I like the idea of pull out sections only during the construction phase. I do not plan on moving or rearranging the layout. I do like turning a section upside down to shake off loose ballast and grass on a folding table and then reusing it on another section.( I did this for a 1ft x 4ft diorama I made for my cubile at work and it was awesome.)  I do like working on a 2ft x 4ft section while watching tv with the wife and not be in the basement by myself.

3) Things change, so in X years or months when I don't want something I can take that 1 module out redo it and add it back in.

4) I was a diorama guy as a teenager. I want finish Section 1 before I do scenary on Section 2. Me being me will want to lay the track work for Section 2 when I do Section 1 so I can operate while I finish Secton 1. I plan on having 12 sections.

When it come down to it. my thoughts are one section at a time may cost more or take more effort in the long run but week to week or month to month it saves on the paycheck. Look at all that track, buildings, etc I bought a basement empire I could of not purchased for a year or two instead of buying it all at once to fill naked plywood.

Drylock and additional lightning is on the to get done this summer list. Great idea for underlayment, I use that as backdrops as its $10 for a 4x8 sheet.  

I came up with a basic module construction design:

I would make a frame out of 1x4s for the 2x4 ply I would then make a lip on the inside (1/2 inch down) and brace so I can drop in the 2x4 ply. This will make the "frame" double as fascia. I am debating backdrop as I want to be able to be on the inside or outside of the layout. I could always have the backdrop hang from the cilgin down and not be attached to the benchwork when I take photos (a mobile 4ft x4ft section).

Another vote for 6 foot module sections