T-TRAK was designed to be a loop on a single banquet table.  To get started, all you need are some basic measurements.

The minimum T-TRAK standards are:

	Width	Depth	Height	Kato track pieces
Single straight	308mm	125mm - 365mm	70 - 101mm	20-000 & 20-040
	12 1/8"	5"-14 3/8"	2 3/4" - 4"
Double straight	618mm	125mm - 365 mm	70 - 101mm	(2) 20-000 & 20-020
	24 5/16"	5" - 14 3/8"	2 3/4" - 4"
Outside corner	365mm	365mm	70 - 101mm	(2)20-110 & (2) 20-120
	14 3/8"	14 3/8"	2 3/4" - 4"
End Cap	732mm	365mm	70 - 101mm	(4) 20-110 & (4) 20-120
	28 13/16"	14 3/8"	2 3/4" - 4"

The outside loop, the red line is wired Blue/White (outside to inside and the inside loop, the yellow line, is wired White/Blue. 

These two tracks need to be 33mm (centerline to centerline) apart.  It is recommended to use a piece of Kato double track to help get an accurate alignment.  (20-042)

Finally, electrical connections are made using Kato connectors from the track on the module to a power pack or to a bus for larger layouts.

This should be enough to get you started with your very own home T-TRAK layout.  Individual modules can be taken to shows as part of a larger layout.

A chart of Kato track is available at: N-Unitrack (katousa.com)

From here, a more substantial set of standards and recommended practices has evolved: 

 T-TRAK Standards.pdf (nrail.org)

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The following is a reprint of the "Guidelines to Interfacing with T-TRAK written in April 2007 by 10 T-TRAKers to help provide a more formal definition of T-TRAK:

Preface

It is understood that T-TRAK modules are designed to be placed on tables that are not specifically built for model railroading purposes and the only “official” T-TRAK module is defined on the web at www.t-trak.org (now https://nrail.org). That being said, model railroaders have a long history of taking a good idea and trying variations. With variations come questions about the very basic elements that must be met in order to interface with other modules. The purpose of this document is to outline those basic necessities for the construction, track placement and wiring of all compatible T-TRAK modules to insure both mechanical and electrical interfaces when joined together with other modules.

This document was developed by a number of clubs from around the United States to define in writing required module interface rules so that problems do not arise when attempting to connect modules from a variety of modelers for display at shows and exhibits.

MODULE SIZE

1) Straight Modules - Module construction techniques and materials are at the owner’s option. Module length is in multiples of 310mm. The module frame should be 2-4 mm shorter than the desired track length to ensure a secure connection at the module interface. Module depth is at the discretion of the modeler. However, recommended depths include 8 1/4” and 12 1/8” with a maximum depth of 14 3/8”. Note: the modeler may choose to build a full-depth module (28 13/16”) or any combination of complementary partner modules that total up to the full depth. An example would be to construct one module 24 1/2" and a complementary partner module 4” deep as illustrated in the diagram below.

2) Corner modules - Module construction techniques and materials are at the owner’s option. Corners (90 degree curve) are 14-3/8 square. One piece corners (180 degree curve, aka a horseshoe corner) in lieu of using two standard corners are allowed as long as track placement is consistent with two 14 3/8” corners. Track placement for all corners is to match community track placement on a straight module

MODULE HEIGHT

The module frames should have a nominal height of 2-3/4" and must be adjustable to 4".

TRACK

1) Number - Two community mainline tracks with Kato Unitrack ends. Mainline tracks are recommended to be 100% Kato Unitrack. All community tracks shall be Kato Unitrack compatible at each end of the module or set of modules. Additional track is allowed for spurs, passing sidings, yards, etc as long as the two community tracks are placed as noted below and operations are not affected.

2) Location – The front track is set back 1 1/2” from the front fascia to the front edge of the Unitrack Piece.

a) 33mm alternate track spacing (RECOMMENDED). Rear track is set back using center to center track spacing of 33mm The Kato Rerailer includes notches along the side to assist with this spacing.

b) 25mm original basic spacing. The rear track is set back 25mm track center to center which is placement of Kato Unitrack with the sides touching. Owners using 25mm spacing bear the burden of providing transition modules to move the community tracks back to 33mm spacing. 

WIRING

1) Module – Not every T-TRAK module will have power feeds, but those modules that do must be equipped with Kato Unitrack power feeds. The front community track will be wired with the blue wire to the front of the module. The rear community track will be wired with the blue wire to the back of the module. In effect, this will yield a blue-white/white-blue configuration for the community tracks. Other wiring for AC accessories, etc. will be at the option and responsibility of the owner.

2) Layout - For layouts that exceed 2 tables or 1 loop in size, the Kato Unitrack electrical components may not provide adequate power distribution. Please reference current Bus Wire specifications available in the files section of the T-TRAK yahoo group web site for guidelines on creating a power bus wire.

NON-CONFORMING MODULES

Non-conforming modules are any and all modules built that do not meet the above guidelines. The owner understands that a specific layout may not accommodate their special modules. However, as long as the modules can fit in the space available and conform to the guidelines outlined above where it will be joined with other modules, there should be no problems. The owner bears the responsibility to insure conformity to the guidelines at the risk of not being able to join in the layout.

1) Straight modules that use non-conforming length and depth may be allowed in a layout if complementary modules are provided that will allow completion of a standard loop without affecting conforming modules from being used. i.e., A module or set of modules that use conforming lengths, but are deeper than 14" must have complementary modules of smaller depth that will allow for a loop to still be created and used on a 30" deep table with the outer tracks spaced such that the outer edge of the outer community tracks match the tracks found on two 14 3/8 square corners using 33mm spacing. Example a double wide by 20" deep module would be allowed if two standard length or one double length module being no more than 8" deep are provided. Likewise a non-conforming length module but with standard depth must have a matching length module to be used on the opposite side of the same loop.

2) A module set consisting of multiple modules that are designed to be kept together for scenery and / or track variation purposes is allowed as long the beginning and ending interfaces meet the conforming modules track placement standard. SCENERY Every effort should be made to show modules with scenery completed to the best of the ability of the owner. Modules under construction will be accepted since they illustrate how a module can be completed. Modules without scenery will be accepted for showing only when needed to complete a layout that would otherwise exclude a completed module. Skyboards are optional but if included should rise to no more than 18 inches above the top of the modules.

CONCLUSION

The intention is to be able to include, rather than exclude, all possible modules. Every effort will be made to accommodate modules produced under earlier versions of the T-TRAK data sheets, but all new modules should be constructed according to these guidelines.

EXAMPLE LAYOUT

Shows the use of various module sizes and both standard 90 degree corners and a 180 degree horseshoe corner.