Electrical Engineering 101: Designing an Awesome Model Motoring Track

Despite my fascination with electric toys, your humble blogger is not an electrician…but fortunately, one of my best friends is! Ain’t that lucky? My buddy Dale, who lives just a few miles from me in north Denver, is a professionally trained “sparky” who, though retired, has a fundamental understanding of circuitry that I myself lack. I’ve never been good with wiring-in my hardcore wrenching days I went out of my way to avoid electrical work, often trading some of the skills I was good at, such as body work and paint prep, to other friends in return for their skills with wiring. Certainly wiring up a slot car track is not rocket science, but right now we’re doing our best to make it as complicated as possible! Last weekend, we hatched a plan to rewire my small (but ever growing) Model Motoring track to improve the versatility of the controls. I’m waiting on some parts to arrive, but once they do, we’ll embark on a rewiring project that should result in some good times in the Toy Room!

Here is the plan:

• Make both lanes capable of being run with either the old-school “cruise control” terminals or the Parma triggers with the flip of a switch
• Be able to run one lane with the cruise control terminal and the other with the trigger if so desired
• To make it possible to reverse the polarity of each track and run it in either direction using either the cruise terminals or the triggers

If that sounds simple to you, you’re smarter than I am, because it didn’t sound simple to me! What Dale came up with is a series of 4 DPDT switches; two will switch between the cruise controllers and the race controllers, while the other 2 will operate only when the Parma triggers are being used to reverse the polarity of the track to change direction, the reason being that the Model Motoring cruise controllers have a polarity reversing switch built into them.

To this end I bought a series of the needed switches, however the plan changed midway through causing a need to add 2 additional switches, which I had to order. The original project box I bought for the purpose was just barely too small to accommodate 4 switches so I had to buy a bigger one of those as well. In addition to this I have acquired 2 additional Model Motoring terminal tracks, which will be wired in to double the number of power taps currently on the track.

Unlike the modern-style tracks that use proprietary connectors that make it very difficult to add power taps, resulting in projects like this to get more power, the old school track has simple screw terminals to connect bare wire too, meaning the only real effort is in running the wire. Since the table in the Toy Room is not designed to drill through like my big table in the main room, the wiring will have to be run underneath my “grass mat”, but of course that’s what the mat is for, so it should work well enough. Even so, I had to buy some new wire as well, since I wanted something thicker than the old speaker wire I’ve been using; I’ll be using 20 ga multi-strand copper wire, which should be thick enough to carry the power I need over the distances required but still small enough to squash underneath the screw terminals…at least, we hope.

The only open question at this time is power: I have a 2^nd DC power supply that matches the one on my big track but I really wanted to use that on the big track since I have this idea that I’d like to power each lane separately. On the MM track I’ve been using a repurposed 17V laptop power supply with pretty satisfying results, so for the time being my plan is to continue using it, unless I find it to be inadequate for my needs once all wires and switches are installed, so this is being left open-ended for now; if I do have to use the DC power supply, I will likely buy a new one for this track so I can use my two identical ones on the big track, but I may bring the one I have into service temporarily for “the H.O. Highway.”

So, this will be a fun X-mas season project! Unfortunately the need to wait on the exact switches I wanted-which were harder to find than you’d think!-will delay the implementation of this plan until probably the 1^st or 2^nd weekend of 2023, but you know I’ll report on all the triumph and tragedy right here at thunderjetheaven.com!