In which a comparison is made between the ridership of some commuter rail operations and that of the Dollywood Express: https://jalopnik.com/the-dollywood-express-carries-more-train-riders-than-10-1849368336
Does Tampa still have the trolley line to Ybor City?
The TECO Trolley still exists
Except for a few systems it is not feasible to know your actual passenger miles. BART with its distance fare system can roughly estimate its passenger miles. Now do not get me started on Amtrak’s failure to promote that for LD>