Unitrack Connectors

I'm planning on implementing a "BCD" circuit which will allow me to use standard SPDT toggles along with a lighted control panel and signals next to the track (using standard bi-color LED's on the control panel and yet to be decided signals on the layout). The idea is that I'll have a control panel with lighted indicators as to switch position, as well as some signaling showing the direction of the turnout on the layout itself. Pretty excited to get this going, as I've decided that the standard Kato 'blue' toggles really don't work well for more complicated track plans. If you want more information on the wiring necessary to do something like this, the plan idea comes from one of the members of the Yahoo! Unitrack forum. I must say, he's been a great help for me in educating me on how to wire these circuits.

Anyway, As I've begun to educate myself on how this will be wired, I also decided that I wanted to build this circuit with as much of the original 'plug and play' capabilities of the Kato Unitrack system as possible. The biggest obstacle is getting more of the Unitrack connectors (affordably...without having to cannibalize any Kato products).

I've found a great article by a gentleman named Randall Roberts on About.com that talks about some of the design of the Unitrack connectors at a level of detail I've not seen anywhere. This may be old news to some of you (and irrelevant to others!) but I did not know that the Unitrack "male" and "female" connectors are actually reversed! Yes, the connector that appears to be the female actually has male pins inside of it, and the same is true for the connector that appears to be the male connector (female pins inside).

And as I went about shopping/searching for the connectors which I will need to attach to the switch machines (the switch machines have the outward looking male connectors, which require what appear to be the female connector, but actually contain the male pins inside), it seems like various vendors (most of them in the R/C field) contradict each other as well.

I did find a really good price on the connectors I was looking for at all-battery.com at US $1.39 each, which is a lot cheaper than buying the the Kato cords! I had to get them with 18 gauge wire vs. the Kato connector standard 22 gauge, but I don't think that will be an issue.

There are other Tamiya connectors out there that LOOK like Kato connectors, but they are a different size (for Unitrack compatibility, what you want is the MINI-Tamiya connectors). I've ordered them to use with building lighting and so forth, which have been designed to run on a separate 12v DC power source. The photo at the top of this post shows the apparent similarity in appearance, but the significant difference in size (the smaller version is the Kato Unitrack plug)! Again, I like the plug and play capabilities of these connectors, and the fact that there are similar, but incompatible types of plugs allows me to easily configure my electrical needs without having to do extensive labeling.

UPDATE (5 Jan 2010):
I've discoverd that the Tamiya connectors do not fit correctly with the Kato Unitrack 3-Way Extension cord (24-827).  The electric conducting plugs and sockets are fine, but it seems the white plastic sockets on the 3-way is not long enough to allow the Tamiya connectors to go on all the way.  I assume that if you modified or trimmed the white plastic on the Tamiya connectors a bit they will slide all the way on, but I haven't tried this yet.  I will provide another update on this once I've tested it.


  1. Enlightening! I don't have any Kato stuff, but I'd seen the connectors in the past, and thought that if I were going to crimp my own cables, I'd use their connectors. I had thought they were these Molex connectors:http://www.molex.com/molex/products/datasheet.jsp?part=active/0019091026_CRIMP_HOUSINGS.xml&channel=Products&Lang=en-US, but your photos, and that excellent link, show that I was mistaken. Thanks for the info!!

  2. Using the mini-tamiya myself with kato. Working fine.
    Tip for the germans:
    you can buy the connectors at Conrad.

  3. I found Mini Tamiya Airsoft Connector Sets (10 Pairs) for $1.76 US. Yes, $1.76 for 10 pairs! I am an American thru and thru but I'm buying Kato track so why not get the connectors from Hong Kong.


  4. Anonymous, that's a nice price. They require assembly, but still, not a bad option!