As per request, I am setting up a new thread for this topic. I am experimenting with RFID for block detection on my budding n-scale 1860's era model railroad. My reason for wanting block detection is that I am also implementing sound using surround-sound system approach, and I need loco location to do this. (Basically I am re-implementing the SurroundTraxx system without requiring the Digitrax block detection system). My goals are: Small enough for n-scale (or less). Low cost (compared to alternatives). Works with DCC+ (Arduino + PC). My initial research prices out 13.56 MHz NFC/RFID detectos at $30 (Grove), and RFID tags at about $2.50. I am ordering a detector and some tags on Thursday so within a couple of weeks I will be testing on my newly laid track-bed.