KarlDL, your post tugged at my heart strings. As a baby boomer, I think there are many like us on the forum who experienced a similar journey through model railroading. When my wife and I moved 10 years ago from upstate NY to Portland, OR to be closer to our children and grandchildren, a stipulation in our house hunting was space for my "dream" layout. I got a 9X14 room in the basement, and after 8 years, just "completed" it in the fall (are our layouts ever completed?). I intend to submit an article on the construction of the GFRR - Grandpa's Funtastic Railroad to O Gauge Railroading magazine that describes building that layout after years of vintage items in storage and modern additions.
As to your question, the first train to run when I completed the track work was my trusty Lionel 2026 loco that my Dad gave me in 1952 when I was 5. Still runs like a charm and puffs O-rings from a liquid smoke chamber I converted from the original smoke pellet unit. Not only fun to watch, but running a conventional control unit, helped me determine areas of voltage drop to add electrical leads from a bus wire.
I included a photo of the consist, as well as a 1948 Lionel catalog that shows the same - for the bargain price of $47.95! A relative gave me the catalog from a house he was clearing out for sale that a hoarder had lived in. I was so excited when I went through the pages and saw my first train!
Enjoy your layout!
Michael