Thank you, everyone, for your comments. I've tried adding a bar for the piston and drive rods for the driving wheels, but nothing I've tried looks right. They're either too big or not in the right place. Maybe someday I'll revisit the idea with a fresh mind.
Are you trying to get away from your sobriquet of "The Dragon Guy"? Because you are defintely flirting with becoming "The Train Guy".
To be honest, there are so very few MOCs I've built of which I am truly proud. I used to be very proud of my dragons, but for the most part I now look back at them with no small amount of disappointment that I didn't do better. Even Formeathan v2.0 has lost points in my mind over time as I critique him over and over, looking to where I could have done better, and wonder what I was thinking when I made certain decisions.
Right now, my train building has produced some very ripe and sweet fruits, and I'm enjoying them immensely. While I may not be the best train builder out there, I seem to have some modicum of talent in that area. Trains have become a permanent part of my thematic resume'
Perhaps once I am finally through with Ulmaris (very proud of Ulmaris, FYI) and tear it down, I can go back to building other castle MOCs with a fresh imagination and new building techniques, and hopefully produce things of which I will remain proud years later.