We know many people who put much effort into building model train setups. But [Rambros] has an entire set 3D printed, and the files are open source, so you can print your own or modify it to suit you.

Electronics people who build model trains. This last seems like ... [Jimmy] at the aptly-named DIY and Digital Railroad channel has several videos on integrating railroad setups with Arduino.

No, you can't go back. But you can build on that childhood memory and work the railroad and ride the rails long into adulthood. That's what the Pensacola Model Railroad Club is all about.