UK Trains - Performance (PPM)

The public performance measure (PPM) measures the performance of individual trains advertised as passenger services against their planned timetable as agreed between the operator and Network Rail at 22:00 the night before. PPM is therefore the percentage of trains 'on time' compared to the total number of trains planned.
A train is defined as on time if it arrives at the destination within five minutes (ie 4 minutes 59 seconds or less) of the planned arrival time for London and South East or regional services, or 10 minutes (ie 9 minutes 59 seconds or less) for long distance services.
Where a train fails to run its entire planned route calling at all timetabled stations it will count as a PPM failure.