Passenger journeys have been reported since the 1840s, partly because they formed an essential accounting measure and also because the figures for railway traffic had to be submitted to government at regular intervals.
Figures are available for most years from 1842 to the present day. The few exceptions include the First World War, when it is not known if the totals were even collated in the usual way. If they were, they do not seem to have been published – possibly because the statistics of troop movements would have been an official secret.
In the case of the Second World War most of the figures were published in retrospect, where it can be seen that during some years the total number of journeys fell, in spite of a sharp rise in ‘official’ traffic. Civilians, on the other hand, were discouraged from using the railway unless their journeys were ‘really necessary’.
Any comparison of totals year on year must be made with extreme caution because various standards of measurement changed over time, such as the inclusion of Irish statistics in the general UK totals until 1923.
Also, older figures before c.1930 excluded season ticket journeys (then calculated at 600 a year for a typical season ticket holder, because Saturday morning was included in the working week). London Underground was probably included. These two factors may roughly balance each other out.
Another statistical publication produced in 1933 by the four main line companies (GWR, LMS, LNER, SR) reports 1,319m for 1923. This is not too far off the earlier totals, and includes season ticket holders but this time excludes London Underground.
Until recently the busiest year since then had been 1945 with 1,371m journeys, including season ticket holders but excluding London Underground. But this total was exceeded in 2014-15, when 1,392m ‘end-to-end’ journeys were reported.
Many modern statistics are those produced by the Lennon ticketing database, which counts multiple legs of journeys separately. Naturally, this inflates the total. 'Ticket-splitting' may also also be a factor which will again exaggerate the totals.
The traditional measure was 'originating journeys', but Lennon counts each 'leg' of a journey (in other words, each train used or likely to have been used en route). Comparable figures from the Government Office Regions, also provided by the ORR and described on its website as ‘Regional rail journeys’, do provide the equivalent of originating journeys, and the regional total for 2013-14 was roundly 1,332m (as opposed to Lennon’s 1,587m).
This suggests that Lennon and other factors are inflating modern totals by 18-19%. Comparisons between historical data and modern totals derived from Lennon should therefore be made only with great care.