I made up a Disney themed train for me and my girlfriend, Megan’s, Christmas tree:
It’s an old Lionel G scale set and some cars from a set I just bought (Scientific Toys I believe). I changed all the rolling stock to metal wheels and Kadee couplers. I’m using some old LGB track and an old LGB transformer. Super simple. Although I plan to add sound next year.
All of her ornaments are Disney themed. But this year she got a Disney themed train to put under the tree.
Here’s the tree…hmm sorry about the angle:

