I don't know what system was used, but must have been a relation at least to the Tellus Carriers we had here at the Corps of Engineers......it sure worked for years and years. It had a wire imbedded in the floor and was used down hallways and into offices etc to deliver small packages and mail etc..... Sometimes someone rode on it but mostly it was just a container on rubber tires that moved about and stopped at prescribed spots and times and then took off again. It was really an impressive setup and always worked fine. Murray Vin: 05962 Lic: DMC-XII Walla Walla, WA