Hands-on Low Voltage Locomotive Speed Controller
Radio control is quite popular these days, but I prefer to set 'em and forget 'em. So I devised this cheap little "throttle" using a 12-pole rotary switch and a few diodes. It yields two reduced reverse speeds and two reduced forward speeds, which are handy for spotting cars, plus flat out forward for hands-off running, with stop sandwiched between. I've built about six, and they work great.
The photos below show step by step construction. It's best built upside down as shown. I usually mount the finished product (right side up) inside the boiler or engine hood, with a smoke stack or muffler, depending on the loco, fixed to the knob, which I just turn with my fingers.
Note that I call it "low voltage" since all my locos use packs of no more than 7.2 volts. If you plan to use this speed control with higher voltages, or in situations which may draw a lot of amps, you might want to use higher amperage diodes, or at least do some tests to see if heat is a problem.
Click a picture to see a larger view.