This was a fun build, bringing back lots of memories. The City Hub fits perfectly in one of the passenger compartments. The original 9V motor and the new Powered Up train motor are exactly the same size, so this was a pretty easy upgrade.
There wasn't any room for the color sensor in the base, so I made it point sideways. Instead of color markers on the track, I've placed them on the side. They fit right in as railroad signs or station markers!
While the 9V system was great fun back then, it's nice to add some intelligence to the train. Now it can stop at train stations, and reverse at the end of the line like a real train, rather than running in an endless loop. 20 years later, I can finally build what I always wanted to build :-)
Do you have any old LEGO sets that you can bring back to life with Pybricks?