Jim gave me this engine, with the sole purpose of changing the horn. How hard can it be?

Well actually it’s trivial. Too trivial in fact. At first I could not figure which decoder this was, and it was obviously one I was not familiar with. I put it on JMRI and that gave me too many options to choose from. I opened the engine and figured out it was a TCS decoder -- specifically a WOW121 Diesel.

The “problem” as far as I can tell is that the horn is simply changed by using the F9 button on the controller. That’s enough to make it cycle through the bazillions of horns available by this decoder. Which means even after I select the proper one, one mistaken push to F9 will change it to something again. F8 seems to do something similar to the bell, or at least change F9 to either select the bell or the horn. I’ll have to dig into the decoder’s manual to find if there’s a way to “lock” in that behavior.

After that, I figured I’d try the engine around the layout and immediately hit a bump, literally. See the picture above? That’s the engine sitting on the tank on the track. The tank’s plastic molding has a bit of a rough edge, and the tank is quite low, almost touching the track. In some places the thing would hit a rail join and get stuck. I tried to smooth the borders of the tank’s plastic molding and that helped a tiny bit, but not much -- instead it got stuck somewhere else where I could see that the track was not totally flat. Just enough to have the engine sitting on the tank and the wheels not have enough pressure to make the engin move.

It’s not my engine so I did not attempt to rectify it since there was no incentive from the owner (“it works just fine for me”). I agree, it works fine as a static piece on a siding. I just changed the bell, which is what I was asked to do.