This is a guest post by reader Malcolm McCaskill based in Hamilton, Victoria.
When visiting Auckland earlier this year, I was surprised how slow the trains were compared with those here in Australia. To see what travel times should be achievable when the dwell time issue is resolved, I assembled timetable and distance data from Auckland, Wellington, Melbourne and Perth, using publicly available timetables and distances between stations from Google Earth. I then used linear regression to develop a relationship for each line between travel time for an in-bound morning peak service and distance between stations. The best relationship was for Wellington’s Kapiti line, which explained 97% of variation, and had an intercept of 1.0 (minutes per station) and slope coefficient of 0.85 (minutes per km). This implies that for each station the combination of deceleration, dwell time and acceleration adds one minute to travel time, and that without stations the average speed would be 71 km/hr. This regression approach was much less successful for other lines, because there was less variation in station spacing. For example on the Eastern Line it only explained 11% of variation. So I used the Kapiti relationship as a benchmark to compare the other lines, calculating travel times using these coefficients from the distance between stations. For all lines except Kapiti, timetabled travel times were unusually long when approaching the terminal station, so I did the calculations for the station before the terminus, because it is not a dwell time issue, and instead one of platform availability. How did Auckland perform ?
Auckland’s Eastern Line is currently timetabled to be 4.2 minutes slower (13%) than the Kapiti benchmark, while the Western Line was 8.8 minutes slower (20%). Melbourne’s Pakenham line was marginally faster (2%) than the benchmark, while Perth’s Fremantle line was 21% faster.
So we would expect that if the dwell time project looks to Wellington for optimal practices, Auckland should achieve travel time improvements of 13-20%. However if it looks to Perth there should be further travel time improvements in the order of 21%. Achieving times similar to Perth should be quite feasible, because like Auckland, its trains are powered by a 25 kV AC electrical system, which enables both regenerative braking and much faster acceleration than the 1.5 kV DC system used in Wellington and Melbourne.
Faster travel times are not simply an issue of passengers travelling faster. It is the equivalent of increasing the fleet size without having to purchase more trains, while also increasing the productivity of train crews, leading to a reduction in subsidies.
This benchmark approach is also useful to estimate travel times post-CRL travel times. From New Lynn to Britomart travel times would decline from the current 34 minutes to 19, or a saving of 15 minutes, while the travel time to Aotea would be 17 minutes. This is equivalent to halving its distance from the CBD.
[editors note] when the new Western line timetable goes live in May we may see some improvements in travel times while AT have say the next timetable change (likely next year) will see them incorporate many of track, signalling and operational improvements being implemented.