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T-TRAK Modules

The minimal standards in T-TRAK permit the flexibility to build modules of all shapes and sizes; however, there are some basic modules that are common building blocks for most layout.  The standard even defines what can be done when building 'non-standard' modules.

Most T-TRAK modules fall into three main categories: straights, corners, and junctions.

  • Straight Modules, which are built in units of 310mm widths.  These are the most common of modules.
  • Corner Modules, which allow the track to turn.  These are usually 90-degree or 180-degree turns.
  • Junction Modules, which combine both straight  and curved track.  These allow for more complex designs beyond your standard oval shape.


Module Wiring

As per the standard, all modules with power feeders are required to be wired using the "blue to the outside" standard.

While not every module needs to have power feeders, best practice is to include power feeders on all  straight modules larger than a single.   

Single Module

Width not to exceed 308mm (12⅛")
Depth up to 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")
Track Length 310mm

Height is measured from table top to the bottom of the Kato UNITRACK

Track pieces can be anything that totals two lengths of 310mm, common combinations are 248mm + 62mm  or 186mm + 124mm.



Double Module

Width not to exceed 618mm (24⅓")
Depth up to 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")
Track Length 620mm

Height is measured from table top to the bottom of the Kato UNITRACK

Track pieces can be anything that totals two lengths of 620mm, common combinations are two 248mm + 124mm or two 186mm + two 124mm.



Triple Module

Width not to exceed 928mm (36½")
Depth up to 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")
Track Length 930mm

Height is measured from table top to the bottom of the Kato UNITRACK

Track pieces can be anything that totals two lengths of 930mm, for example three 248mm + 186mm .



S-Transition

Width not to exceed 618mm (24⅓")
Depth up to 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")

Height is measured from table top to the bottom of the Kato UNITRACK

NOTE: Caution is necessary when building the S-Transition because the left and the right are mirrored versions of each other. You can not simply build two identical modules, and turn the one around.

The S-Transition is built to be the same size as a standard double module, and transitions the track from the 'front' edge to the 'back'. The standard 1½" setback is maintained at the ends on both sides of the module. S-Transition modules are often used in pairs, and any module placed between them can be placed "backwards" to the common viewing angle.



S-Transition Track Pieces:

  • Red line: S29 + R348-30° + straight + R315-15° + R315-15° + S29
  • Yellow line: S29 + R315-15° + R315-15° + straight + R348-30° + S29

The straight segments in the center will vary based on module depth, most common arrangement includes the extendable track [20-050]:

S124 +  [20-050] + S62 


Small Corner Module

Width 365mm (14⅜")
Depth 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")
Track Radius 282mm / 315mm

Height is measured from table top to the bottom of the Kato UNITRACK

A 282R/315R corner is the original corner module, and is still the most common.  Sometimes referred to as a "standard corner".  Small corners are part of the standard because they are the largest radius that will allow an overall of track to fit on a "normal" banquet table (~30").  

 Although this can be misleading, since the larger corner sizes also meet the standard



Larger Corner

Width See the Pro-Tip below
Depth Same as Width
Height adjustable from 70-101mm (2¾ - 4")
Track Radius

"medium": 348mm / 381mm
"large": 447mm /480mm
"extra-large": 481/481+33

Height is measured from table top to the bottom of the Kato UNITRACK

Note: Although they have become quite popular, larger corners are considered non-standard size because they do not fit on a single table.

The most common way to create the larger corners is using the Kato Double Track Superelevated Curve pieces. Note that there are special "Approach tracks" needed for the superelevated.

If you are doing a 90-degree corner using the Superelevated track, you will need:

  • Approach Track Right (22.5 degree curve)
  • One Superelevated Curve piece (45 degree)
  • Approach Track Left (22.5 degree curve)

Review the Recommended Practice document for details about using corners/junctions of differing radii.

Pro-Tip

When determining how big your module needs to be for a corner module, add 50mm to the largest radius.

Track radius is measured to the center line of the track, so you need to add the distance from the center of the track to the edge of the Kato track piece.  And then add the 1½" set back required by the standard to get the full width & depth needed for a 90-degree corner. 

Kato Track is 25mm wide, or 12.5mm from track edge to center. The set back of 1½" is 38.1mm.  12.5+38.1=50.6mm, or roughly 50mm.

For example, if you are going to build a "medium corner" using 348mm and 381mm radius curves, the module would be 431mm (16.97") square  (381 + 50 = 431) .

Endcap

Width (2x Radius) + 101mm
Depth Radius + 50mm
Height adjustable from 70-101mm (2¾ - 4")
Track Radius variable

Height is measured from table top to the bottom of the Kato UNITRACK

An endcap is just two "corner modules" as a single module. So they turn the full 180-degrees in one module. They are built in the same radius as the small or larger corners.

To determine the width & depth, you can use the outside track radius. For example, if you are going to do a 282/315 endcap:

Width = (2 x 315) + 101 = 731mm or 28¾"
Depth = 315 + 50 = 365mm or 14⅜"

(see the pro-tip to learn where the 50 and 101 additions come from. )



Inside Corner

Width ~ 550mm (21⅔")
Depth ~ 550mm (21⅔")
Height adjustable from 70-101mm (2¾ - 4")
Track Radius mix of 282/315/348

Height is measured from table top to the bottom of the Kato UNITRACK

Module width & depth above are just approximate.  Those are assume the module was a complete square, with the track interface sides at 12".  But at a minimum you have to cut off one (inside) corner.  The example here actually cuts off the inside and opposite corner.

Track pieces, as depicted here, is the ideal set because it keeps the minimum radius of 282mm for the "yellow" line and 315mm for the "red" line.  Early example of the Inside Corner used 282mm track on the inside curve, which is the red line (since the curve in introverted from the normal).  




Inside Curve Track Pieces:

  • Red line: R348-30° + R315-15° + R315-15° + R348-30°
  • Yellow line: two R315-15° + two R282-15° + two R315-15°


T-Junction Module

Width not to exceed 595mm (23½")
Depth 365mm (14⅜")
Height adjustable from 70-101mm (2¾ - 4")
Track Length 597mm (non-standard)
Track Radius 282mm

Height is measured from table top to the bottom of the Kato UNITRACK

The original T-Junction was designed by Steve Jackson, so is sometimes referred to as a "Jackson Junction".  Because it is the only one that will still fit on a table, it is also referred to as a "Standard Junction"

The straight legth of track (597mm) is not a natural length for Kato track. You will need to use the adjustable track piece [20-050], or a custom cut piece of 101mm.  


Larger Junctions

  Small
"Jackson"
Medium
DesMoiNTRAK
Large
"Branchline"
Extra Large
Width 595mm 727mm 925mm 993mm
Depth 365mm 431mm 530mm 564mm
Height adjustable from 70-101mm (2¾ - 4")
Track Length 597mm 729mm 927mm 995mm
Track Radius 282mm 348mm 447mm 481mm

Height is measured from table top to the bottom of the Kato UNITRACK

All Require use of adjustable track piece [20-050], or a custom cut piece.

Note: Junctions larger than the "Jackson Junction" are considered non-standard size because they do not fit on a single table.

Review the Recommended Practice document for details about using corners/junctions of differing radii.

Non-Standard Modules

Model railroaders are creative people, and sometimes that creativity does not fit into a formal standard!  The good news is that the T-TRAK Standards document actually has accommodations for being non-standard.  In it's simplist form, the idea is that if you have a "non-standard" module, you can have a second module that brings it back into "standard".  Here are just some scenarios illustrating how this works.

Deep Modules

The standard for straight modules of "not to exceed 365mm (14⅜ in) deep" is based on the idea that anything deeper would interfere with the module behind it. If there was a 'thinner' module in that location, than the 'deep module' would not interfere.

Odd Track Placement

(yards that have the track down the center instead of 1.5 offset)

Odd Lengths

Sometimes a kit or a scene just won't fit on a 'standard module'.  You can build a non-standard length module, but then you have 2 options:  

  1. Build a second non-standard module of equal length to be used opposite the first one
  2. Build a second non-standard length module that adds enough length to the first one to bring it to a common standard length.

Technically, there is a third option for 'odd length' modules, and that is to use it in a way that doesn't impact the overall layout or other modules. For example, you might use an odd length in section of the layout that doesn't have a loop.  This third option leads up the the last example...

Unique Shapes

Modules can be built to address a specific need or desire, such as the star junction, or a balloon module.  These modules (usually) don't have a specific partner module to bring things back into standard like the previous examples, but they are still useful in a layout because they do negatively impact the other modules.

Examples

All of the modules in this example are taken from real word examples.  This shows the versitlity of T-TRAK, and how non-standard module can be used.   All of the modules in red are 'standard' modules.  The light blue modules are a pair of odd lengths set opposite each other in the loop.  The two pink illustrate a deep depth, and the matching skinny module working together. The green star junction is a unique shape module.  The yellow modules, taken as a whole, is an example of the unique shape balloon module.  But careful observation will notice that it is made of one endcap (a 'standard module') and two 'non-standard' modules with odd track placement working as a pair to bring things back into compliance with the standard modules on either side of it. 

Bringing Non-Standard Modules to Shows

Using non-standard modules on your own setup is one thing, but what if you want to take that module to a show? The key with using ANY non-standard module is communication with the layout coordinator.  When you are at home, or setting up all by yourself, you are the layout coordinator. When you are trying to setup with others, you need to make sure the layout coordinator knows the details about your non-standard module.  

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