Here are some doodles I've put together. Note that I haven't actually =built= any of these layouts! Most of them were designed and assembled using Visio, a drawing program that lets you assemble objects and paste copies of them all over the place. The size of any 'errors of closure' (those nasty oddly-shaped gaps) were determined by examining these drawings.
Note for the Pinwheel, T, Z, and L shaped layouts-- they won't fit on regular banquet tables without additional pieces of plywood to fill in some 'open air' areas.
Since T-Trak's 'big brother,' N-Trak, has created layouts using central junctions with arms of the layout heading off in all directions, why shouldn't T-Trak be able to do the same thing?
The 6 layouts below attempt to fill that need. The diagrams below show 'shortened' arms. Any arm can be extended to infinity; just add identical lengths of modules on each side of the table.
The arms of all layouts are designed to fit on 30" wide tables. The hubs of all the layouts need extra support to keep all of the modules on top of the tables.
Layout #1, the "Plus" layout, is a simple layout that uses 12 identical corners to create branches heading in 4 directions. Both main lines traverse the entire layout.
Until you insert modules in all 4 arms the layout is composed of nothing but "S" curves. You'll need at least 8 straight modules to cure this problem.
The hub needs an added 48" x 48" piece of plywood.
Layouts #2 and #3 each use 8 junction modules to create 'Plus' modules.
Unlike the first plus, layout #2 creates an inner loop that stays within the hub. The outside main traverses the entire layout, and each arm has a loop using the inner main that stays on the individual arm.
This layout can be expanded in all 4 directions. Along the major axis, the inner loop can be expanded, or the end loops, or all 3.
The junction modules in the hub need either an extra leg where the 2 curved tracks come together, or a 4 foot square of plywood for support.
Layout #3 also uses 8 junction modules. This time, however, the layout is symmetrical, although the arms 'pinwheel' around the hub, rather than being directly opposite each other.
Expansion is limited to the 4 arms.
The junction modules in the hub need either an extra leg where the 2 curved tracks come together, or a 6 foot square of plywood for support.
Layout #4 uses 4 junction modules and 'pinwheels' in just 2 directions.
Expansion is limited to the 2 arms.
A 48" x 53-1/2" piece of plywood is needed to support the parts of the modules that would otherwise be over the abyss.
Layouts #5 and #6 expand the Pluses into Hexes-- 6 arms each. To accomplish this end, six 30 degree segments of track are used to curve the arms in the right directions.
Layout #5 is similar to layout #3: it uses 12 junction modules and six 30 degree segments to link the arms. It has an inner loop that stays in the hub, the outer main traverses all of the arms, and each arm has a dedicated loop using the inner mains.
Unfortunately, the hub loop in #5 is loaded with "S" curves. Ideal for Thomas the Tank Engine or other short equipment.
Layout #6 is similar to version #1; it uses 3 corners plus the 30 degree segments for each of the arms. Both mains traverse the entire layout.
Depending on how #1 and #6 are powered, you may only be able to have 2 trains running on a rather large layout. You may have to use insulated rail joiners and create blocks, or run multiple trains on 1 track and keep a close eye on things, or run with DCC.
Numbers #2, #3, #4, and #5 can have a similar problem on the long outside main. Depending on how long each arm is, you may want to run multiple trains on the inside main on each single arm.
Modules #2, #3, #4, and #5 have dedicated loops that never leave the hubs. The hub loop for layout #2 can be extended, but the other loops are fixed size. In layout #3 the hub is only about 4' across. In layout #4 the loop is just under 8' across.
Note for the T-shaped layout-- there is an odd-sized filler piece required. From examining the diagrams and scaling, it appears to be 8-1/2" wide x normal module depth.
These diagrams are plotted over outlines of 30" tables. Note that some of the corners hang over the edges of the tables; some plywood to hold the pieces up are required.
The first diagram is for Basic 25mm track spacing, the second, for Alternate 33mm track spacing.
Note for the the L-shaped layout-- it appears there is a 2" error of closure in each direction. A big enough layout could 'cheat,' and jimmy things around until they matched up.
The Australian T-Trak group mentioned something about "E-shaped" layouts and I got carried away again. Here are 3 variations on the theme. All three use 282/315mm-radius 14-3/8"-square alternate-track-spacing corners.
The first layout uses Junction Modules to form the 3 legs of the E. Because junction modules are an 'odd size' (22 mm shorter than 2 single modules), there will be gaps of 88 mm to be filled in.
The second layout uses junction modules for the central leg, and 2 variations of Outside Corners for the outer legs.
On the left, standard corner modules are used for the inside and outside corners. Special filler modules, 11-1/4" long, are placed next to the outside corner to make things come out even. I don't believe these filler lengths will change even if you use deeper modules. A piece of plywood will be needed to hold up the inside corner.
On the right, "offset modules" and a standard corner are used for the inside corner. This keeps the modules on the table; you won't need a piece of plywood to hold things up.
The length of the filler modules on either side of the outside corner will depend on the module depth of the offset modules. For 8-1/4" (original module depth) offset modules the filler modules will be 8.3" long (as shown). If your offset modules are 12" deep (and assuming the module is symmetrical) the filler modules will be 4.55" long.
The calculation for the filler modules is shown in the "Specialty Modules" section under "Outside Corners." Click on the diagram to show the calculations. The box around the Y= and X= shows the calculation.
The red lines show where the inside/outside corners 'come out even;' where both sides of the table line up perfectly.
The third layout replaces the right-hand leg with an inside corner. Assuming the corners are all the same size, the size of inside corner module depends mostly on the module depth. The 18-1/4" square will line up with the back edges of 8-1/4" deep modules. For 12" deep modules the square will be 4" larger, but the additional size is only to line up with the back edges of the deeper modules.
Here are 6-1/2 yard designs I've been doodling with. They're staging yards for the most part, although some have hopes of becoming a prototypical yard at some time.
All of them use the Alternate 33mm track spacing standard.
A is 12-1/2" deep x 8-modules long. It incorporates 2 double crossovers. Five storage tracks are shared by both mainlines. The design acts as an 'offset' module; another offset module is required to return the mainlines back to the front of the layout. The double crossovers may cause fun with wiring...
D is actually 2 yards. Each yard is 13-1/2" deep x 8 modules long, and has 6 storage tracks. The yards are complimentary-- the one on the left provides storage tracks for the inside main, the one on the right has storage for the outside main.
B and C are full-table-wide yards. As drawn, both are 10 modules long. The size will require serious transportation, and each takes a table and a quarter! Both are intended to work with Alternate 33mm track spacing, possibly with 2 alternate corners adjacent to the yard.
B is actually 2 yards on a single base. Double crossovers at each end of the yards allow you to mix and match traffic. Each has 5 storage tracks, 10 stub tracks and a couple of tracks that can be used as switching leads.
Although layout C is as big as its neighbor, it is a single yard for each track. The module occupies the full width of a table, but on one side the mains just travel through. On the yard side, the mains swing to the center of the available space, so each main has 7 storage tracks. Each main only has to navigate 1 turnout at each end of the yard. Because the yard is a pyramid shape, the tracks for the inner main are a lot shorter than those for the outer main.
These layouts are similar in capacity- each main has 3 storage tracks. E & F are 13-1/2" deep; G is 16" deep. All are 8 modules long. I'm pretty sure the gaps that show in the diagrams are a figment of the design program I use.
Layout E is centered on the module, so half-offset modules are required to swing the mains to meet the yard. There are a couple of stub tracks probably suitable for spare motive power.
Layout F starts with the tracks in normal position, and swings them aside as needed. The inner main gets the shorter tracks.
Layout G is really just layout E shifted forward a few inches. After staring at the diagrams for ages, and making a lot of sketches, I came to the conclusion that I liked the extra capacity of layout E, but didn't like the idea of the half-offset modules required to use it. So layout G cantelevers 4" of module in the thin air at the front of the module, relying on the remaining 12" of module on the table to keep things from The Abyss.
Although G is a larger module, the extra depth behind the tracks is well suited for some bas-relief scenery.
E, F, and G all have a couple of corners that could be used for some short spurs, probably for spare motive power.
Although I like the double yards of "D," transportation begins to take its toll as modules grow.
I have built myself one of yard "G." I used Kato #4 turnouts, and they work just fine. I haven't electrified them because they're close enough to the front of the layout. Although I haven't had any problem with turnouts holding position, Peco brand turnouts have a spring action that holds the turnouts to the desired route more strongly than Kato turnouts.
I built my yard "G" in two 4' sections. I built them out of GatorBoard, and the two sections can be clamshelled together to make a box. The package is about 4-1/2' x 20" x 16". I ought to build some nice end caps to protect the rails and keep out dust and debris, but that's a future project.