09.09.15
Network Rail blames rocketing dwell times for poor performance
Network Rail says there is “strong evidence” that passenger journey growth is directly impacting peak performance in London and the South East (LSE) because of rising dwell times on an already “saturated network”.
In a report seen by RTM, submitted as evidence to the Office of Rail & Road (ORR) during its investigation into poor performance on Southern, Govia Thameslink (GTR) and in Scotland, the infrastructure owner stated that passenger journey growth in 2014-15 exceeded the Strategic Business Plan’s (SBP’s) anticipated 3% compound growth by 40%.
The ‘Impact of Passenger Growth on Train Performance’ report stated “there is strong evidence that weekday peak performance in LSE has been directly impacted by this increase through extended station dwell times on a saturated network”.
Network Rail added that “in simple terms” the London morning peak Public Performance Measure (PPM) has fallen by 5%, and this has generated a 2% drop in LSE weekday PPM.
It was stated that the “most probable relationship” between increasing passenger volumes and service delays is at stations, reflected in the ‘dwell time’ for individual trains.
LSE weekday services account for 45% of national PPM, so this drop resulted in an overall decline of nearly 1% in England & Wales. The report suggests that 40% of this decline was “unexpected” for 2014-15, as most of the SBP mitigation plans for growth were associated with upgrades to be delivered later in CP5.
Rising dwell times go largely unrecorded, but they have the most acute effect on performance where there are “multiple closely-spaced station calls, heavy volumes of commuter traffic, complex junction arrangements and large numbers of services – the LSE sector”.
As well as in the LSE area, these symptoms are also observed on services around Birmingham, south Manchester, Merseyside and Glasgow.
Network Rail’s report revealed that Arup research for the Crossrail and Thameslink projects shows a modelled correlation between the volume of passengers boarding and the train berth time. If no passengers are standing in the train vestibule the time taken for a given number of passengers to alight is shorter than that for an equivalent number to board – around 5 seconds for every 30 passengers. Where there is a mix of boarding and alighting passengers there is an exponential deterioration of station dwell times.
Following the ORR’s investigation, which led to the regulator fining Network Rail £2m for breaching its licence agreement, it noted that “whilst it is possible that a greater than forecast increase in passenger growth could have adversely impacted performance in 2014-15, we do not consider that the report provided by NR conclusively proves the link to, or the extent to which, passenger growth affected Southern and GTR’s performance in 2014-15”.
Network Rail said that resolving the issue of dwell times is a significant challenge for the industry.
Its ‘Impact of Passenger Growth’ report, submitted to the ORR in late May this year (but only seen by RTM this week, following a Freedom of Information request), said the organisation’s Business Planning team will lead a review of good practice opportunities, and work out how best to mitigate the problem.
And a new workstream will undertake a greater level of analysis surrounding the impact of passenger growth on performance. This will be aligned with modelling work and combine cross-industry skills to review passenger data, and establish an analytical approach to understanding and predicting the impact of passenger growth on performance.