Train punctuality

[Colm Moore]

While reading this: http://www.irishtimes.com/life-and-s...book-1.1700481 it struck me that it is interesting that train punctuality is measured against the amount of time (minutes*) the train is late, not the amount of time (minutes) the passenger is delayed. Sometimes it 'pays' train companies to cancel a train that would be excessively late, perhaps the worst examples being back in 2009-2010 in Britain where trains were cancelled wholesale on some days, simply because up to that point in the reporting period** there had been few cancellations, but a lot of delays.

Now, sometimes cancelling a train in a section of track that is crowded with delayed trains is justifiable - insisting on a DART service operating Connolly-Malahide, when there are a bunch of delayed Bray/Greystones to Malahide DARTs stuck from the city to Malahide does make sense as there is no impairment to the DART service. However, that extra DART may disproportionately affect a following Enterprise. Similarly, cancelling an individual service can allow service be restored to the timetable more quickly.

However, I think there is an argument that the way reliability (did the train run?) and punctuality (was it on time?) are calculated.



* Strictly speaking the benchmark is what percentage of trains are delayed by more than X minutes,where typically X is 5 minutes for short trips and 10 minutes for longer trips. Irish Rail use a modified version of this.
** There are 13 four-week reporting periods per year. This avoids the problem of month length skewing the number of weekend days in a particular reporting period.