There is SO much potential in actual model trains. HO scale has standardized digital control (DCC) but the advanced high-end controllers (like Märklin CS3) are crazy expensive, and so are trackside signals. At this point any engine could be programmed for autonomous operation under the control of centralized signaling that implements a system-wide operating schedule... if you can just figure out how to cram the electronics into the loco body shells and wire up their internals. If anyone knows where to find the "state of the art" of distributed loco intelligence, please provide pointers !