Learning to take a dump

I bet that caught your attention.

Back in the fall, someone in my local train club sold off a bunch of equipment from a guy who was closing down his railroad. Among the items available were a couple of log cars, something I had been thinking about adding to my collection. I usually wait-and-think with the result that everything good is gone before I'm ready.  Not this time! I made a quick offer for one of the log cars. The price was good so when I was offered both for about 50% more, I went for it. When I picked them up, I found out they came with a piece of track with a middle rail to trigger the car to dump to the side.

The cars are in fabulous shape and in their original boxes. They are MTH Operating Log Cars. The instructions talk about hooking up the middle rail to a separately-purchased switch box to activate the dumping. That system was more than the cost of the cars and I figured I should be able to figure it out without much trouble. To start working it out, I thought I'd identify the path of electricity that would power the dump motor. Each truck has what looks like a metal pickup in the middle. I figured either the middle rail powered the motor through the two pick-ups or each truck had a connection between the pick-up and one side of the wheels. I first tried testing for electrical continuity across these potential pathways. 

One truck with the electric pick-up

My testing for continuity was reading infinite resistance (or at least more than 200 kOhm) for every combination I tried. I was really expecting to find some path that had a reasonable resistance that would identify the path. [Note: I tested a hobby motor from my Arduino kit and it reports about 5 Ohm across the motor so I think my logic was reasonable.] Maybe since the log car I was testing was used, it was damaged and wouldn't work? It seemed unlikely since otherwise the car was in brand-new shape; not a scratch to be found anywhere. When the second log car had the same readings, I was confident I didn't know what I was doing. 

Where do you turn when you don't know what you are doing? The Internet! (Or as my wife calls it, "the All-Knowing.") I searched online for guidance or someone's description but didn't find anything helpful. Next stop was an online forum. Here I had to admit my ignorance but at least I couldn't see anyone laughing.  Several folks chimed in with a couple pointing back to the switch system but no one with experience with these cars. I probably should have stopped there as the dumping wasn't the reason I wanted the cars and I'm not even sure where on my layout to put the track with the middle rail. 

Nonetheless, I was sucked in. It seemed like it should be so simple and dumping the logs was sounding more and more cool. One forum post did lead to a reseller who had the switch package from MTH at an acceptable price and had a couple of other things I was looking for. In for a dime, in for forty bucks. 

The switch box is pretty complicated with four switches and about a dozen wires. One switch lets you isolate the section of track with the dump car on it. It connects to a set of wires that also connects to the neighboring track to draw power from it. I guess that lets you keep running trains on the mainline and cut power her so the car stops. Since I'm running DCC that isn't necessary. A second switch lets you only apply power for accessories (I haven't really figured that one out but I don't have any cars with extra powered accessories so it hasn't been worth pursuing.) Then there are two switches that control power to the center rail so you can control two sections from one switch box. You can even connect multiple switch boxes together to get a whole line of then and dump logs anywhere you want on your track (for enough money).

After following the instructions and wiring everything up, I tried it and rrrrrrrr the motor ran and out dumped the logs. Everything worked! But I really didn't want to have all these wires and the switch box and I really hoped to run this from my Arduino at some point. So how could I simplify the set-up? Removing the isolation function is fine.  I have to stop the train in the right spot anyways so I don't see the benefit of the section being isolated. Then I disconnected the switch to the middle rail and just applied 15 V to the rail. Rrrrrrr the motor ran and out dumped the logs. That simplifies things. And if I just apply the power directly to the pick-ups under the trucks? Rrrrrrr the motor ran and out dumped the logs. That's it. Just apply 15 V, what my Piko starter kit power supply puts out as accessory power, to the middle rail and you get a pile of logs. I even discovered that if you put other things, like leaves or flower bulbs, in the car, it will dump those too. Who knew???

So this is how I learned to take a dump of logs. Hopefully, if anyone else in the future of railroading wants to do the same, they now have a little more insight. Or maybe they will just look at the obvious solution and try it and discover it works. Maybe one day I will be that smart.

And if you are looking for a fancy switch box, I just might have a spare :)

Until then, happy railroading.