T-TRAK Wiring

The T-TRAK wiring standard is based around the Kato connector.^† While every module does not need be wired^††, those that are wired are required to have the track wiring end with a Kato connector (pin side). The busline is required to have the receptacle side of the Kato connector.

Kato track wiring uses blue and white colored insulation, and this same color-coding is used in the T-TRAK standards. This has lead to referring to the T-TRAK module wiring standard as "Blue to the outside" or "BWWB" (blue-white-white-blue).

^† The Kato connector is very similar to the Tamiya mini connector, but not identical. See the connector comparison sidebar for details.

^†† There is no rule about which modules are required to be wired, but it is recommended to wire all straight modules, especially doubles or larger.

Resources

Benefits of BWWB

T-TRAK Standards

T-TRAK Wiki Article

Talkin' T-TRAK presentation

Module Wiring Standard

The T-TRAK module must be wired so that the blue wires are on the outside rails:

Each track will be independently wired, therefore each module will have two sets of the blue-white wiring. The outside rails for each track will be connected to a blue wire, and the inside rails will be connected to a white wire.

Module Wiring vs. Layout Wiring

One feature of working with T‑TRAK is the distinct difference between "Module Wiring" and "Layout Wiring". While it may not be obvious at first, this feature highly simplifies both the building of the module, and the planning and building of a larger layout. (More on these benefits later).

When building a module, remember that the modeler only needs to have feeders from the track, and these feeders must terminate with a Kato connector (or compatible). The polarity of that connection does not matter yet, because we haven't set up the overall layout yet. The polarity of the connection comes into play once we have multiple modules connected together, i.e. we have a layout. This is why the separation is one of the benefits - the layout planner does not have to worry about polarity when connecting modules, only after they are connected.

The Benefits of BWWB

The Blue-white-white-blue standard is not just some random choice, it has now been tried and tested for over 25 years. That alone should put the discussion 'to bed', and yet it is not uncommon for people new to T-TRAK modeling to find it confusing.

Vic McTee has a great article (written in 2017) over at the T-TRAK wiki illustrating how a BWBW wiring would limit T-TRAK layouts, not simpify things.

Terrry Moore explained BWWB wiring in his Talkin' T-TRAK segment of the August 2025 ZoomTRAK session.

Connector Comparison

The Kato connector is very similar to the Tamiya connector, but not quite identical. Both are the same size, and are keyed using a square and round housing placed in the same orientation. But upon close inspection, you can see that the Kato square has it's corners rounded off. So plugging a Kato pin into a Tamiya receptacle is rarely a problem, trying to plug a Tamiya pin into a Kato receptacle can be difficult. If you are using the Tamiya pins, you are encouraged to shave down the corners on the square housing to allow for an easier connection.

Closeup of pin sides of a Kato connector (left) and a Tamiya connector (right)

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