Summary
Rail reliability is not just whether a train runs. ORR measures show punctuality and cancellations in different ways, so you should check more than one indicator before trusting a commute.
Definition
ORR rail performance statistics include several measures used to understand passenger rail reliability. On Time measures the percentage of recorded station stops that arrive early or less than one minute after the scheduled time. Public Performance Measure, or PPM, measures whether a train arrives at its final destination within the allowed lateness threshold, commonly 5 or 10 minutes depending on service type. Cancellations measure trains that are cancelled or part cancelled, with weighted scoring used in ORR releases. For a buyer, these indicators help compare operators or routes, but they should be paired with your own journey time, connection risk and peak hour ground truthing.