You jest, but with an ESP32 flashed with ESPHome and a few dollars of electronics to regulate the power, I think controlling model trains would actually be quite doable. Your biggest challenge is probably dealing with network/scripting latency for events that need to happen in quick succession, like when dealing with switches.

Or, if you consider Lego DUPLO trains to be model trains, there's this: https://community.home-assistant.io/t/lego-duplo-train-contr...

Edit: there's also this https://github.com/aaron9589/esphome-for-model-railroading for the more serious model railroad enthusiast, though I'm not 100% sure if that actually controls the trains themselves (or just the switches and lights)

It could also automate ordering pizza delivery and the tipping process to "Keep the change, ya filthy animal"

There are dcc systems that run on Arduino or raspberry pi, and expose an API interface. Could control one via home assistant