I love the idea, but implementation is a bit over my head. I'm not an EE and I've never done anything with an Arduino. I really don't know where I would begin.
I've been hard at work designing complex layouts for my 12 x 18 space featuring multiple routes. Basically three short trains alternating among two mainlines. I would love to set it up as an automaton (think "demonstration mode" for visitors) Or even better, have a computer-controlled passenger train that stops at stations, while the human operators try to complete a switch list with a local freight.
I was mulling implementation with the Lionel LCS sensor track, and layout control through an iPad. Or go all-in with JMRI / C-MRI. Although a lot of the equipment I have is Legacy and DCS I'm not wedded to either of those systems; in fact I would prefer a non-proprietary system. With 40+ switches in 200 sq ft some kind of computer-assisted visual control and routing is mandatory. Especially if I want my guests to take an active role in operating the layout.
Earlier this year Lionel introduced track with built-in LED lights. I think it's mostly a gimmick for Christmas tree layouts. But some variation of that could be a visual cue directing visitors where to go. Imagine... when a train passes the track the LED is extinguished and the "passengers" are picked up, etc. Just a thought... With the nature of my layout designs, if some randomness could be introduced it could make for a highly varied operating experience.
Another possible use of your RFID tags, would be with locomotive sound. All the Fat Boys in the world won't match a subwoofer and high-quality monitors (speakers) under the platform. What if the sound were to modulate based on the position of the loco as it moves around the platform? Just thinking aloud here...
Your work amazes me, but I struggle to learn by watching videos. Maybe you could do a clinic at a future York or Cal Stewart meet (do they still have those?) As always thanks for sharing!