I was just tinkering with Chester's amazing climb of 1.2m from 3.0m to 4.2m, supposedly down to the cleverer redistribution of Merseytravel PTE zonal tickets.
Previous stats had been using a model based on 2008 usage, and it has now been updated.
Since 2008 the service from Chester to Liverpool has doubled in frequency (2tph to 4tph) and the PTE Daysaver tickets are now a cheaper way of buying off-peak travel instead of railway Cheap Day Returns.
Then there's the various PTE season ticket combinations.
Analysing the 1.2m increase, if we assume 333 days in a year to simplify the arithmetic, that's 3600 extra entries/exits a day.
For an 18-hour service day that's 200 e/e per hour.
At 4tph (8 arrivals/departures), that's 25 passengers boarding or alighting per train.
I reckon that's about half a typical trainload, maybe more.
How can the system miscount half a train's passengers?
The only explanation I can think of is that incoming passengers on Daysaver tickets would not be counted at Chester, only at the origin.
So all those scousers heading for Chester Races would be miscounted.
Going the other way (Chester passengers heading to Aintree and the like) would be counted at Chester as the station of origin, but not at the destination.
Or have I missed something?
If this just a redistribution, you would expect decreases of about the same overall numbers at other stations, but there don't seem to be any.