CNWDON,
Before getting too far along, after seeing what some other folks have to say, I think it would be a good idea to clearly define the problem, and to insure your track wiring is up to snuff as well, to eliminate that as a problem. George (GGG) also got me thinking with his post on modifying the locomotive and as I think on it, that may be a better way to go depending on exactly what we are dealing with. So, in order to understand exactly what is going on, and what options are available I have some questions.
1. As others have suggested, have you had a chance yet to see if the high voltage reading is simply a 'no-load' condition that could be solved by simply placing an always-on lightbulb across the transformer's output.
2. For clarity, what you have now is ERR electronics inside the pre war locomotive to run it with TMCC?
3. Do you only have the single pre war locomotive that is a problem, or are you running several that would need a 'fix'?
4. Are you running the pre war locomotive on the same track/power block with any other engines with modern electronics in them at any time?
Once we know exactly what's going on, it will be easier to see if modifying the engine or adding something to the supply to the track is a better option.
As for the Arduino stuff, it is a lot of fun to tinker with. As to how hard it is to learn, I have a hard time judging that for other folks. I was taught electronics and computers from a very young age and often pick up new technologies relatively quickly. That said, the Arduino project has a wealth of free tutorials online, an extremely helpful community forum, and the platform is designed to be easy to use. As it related to things someone might want to do on a model railroad, once you've gone through the examples in any starter kit and understand how they work, you should have no trouble doing whatever you need for your train layout as far as controlling lights, relays, and the like. Arduino is also rather awesome, in my opinion in that it is an open source project. The board designs are freely available for anyone to produce, which has led to such low costs that the off-brand clones are only a few dollars. I do recommend purchasing at least one of the genuine boards at some point as the Arduino product is constantly improved and funded through sales of the genuine boards and donations. Once you feel you've done your part to fund the developers, however, there is no difference in a genuine board and the $2-$5 versions.
JGL
