This year the first of our new electric trains will arrive and one of big benefits of them will be that they have faster acceleration than the clunky diesel trains we have now but the question is just how much faster they will be. For some reason it is something that Auckland Transport have been pretty reluctant to actually talk much about which I am guessing is due to them not wanting to get peoples expectations up. We however are not AT and are free to talk and speculate all we like so with that in mind, some time ago I built a model to try and work things out. I actually blogged about it back then but at the time I had only showed the western line, with this post I thought I would look at the whole network. Before I go into the results, for those that are interested, here is an explanation as to how I have worked the times out:
First I have worked out the distance between each station and for each leg of the journey I have assigned a maximum speed that the trains can travel and I have kept most of the network at 80kph with the inner sections at 60kph. When the EMUs were announced AT said that they would be able accelerate and brake at 1m/s². Based on that I then worked out how long, both in time and distance it would take to reach the top speed and slow back down again for each section of track. For those interested it takes 22 seconds and 247 metres to reach, or slow down from 80kph based on that acceleration of 1m/s². The next step was to work out how long the train would travel at top speed. To do that I subtracted the acceleration and braking distance off the distance between stations and worked long it would take. For each station I then added in a dwell time to represent how long it would spend on the platform. To be conservative i generally used 45 second however for busier stations I used 1 minute. I then added the time spent accelerating, braking, at top speed and the dwell time together. Lastly to try and be conservative I added in a multiplier of an extra 20% to account for things like slow drivers, corners and junctions which that then gave me an overall result for each station.
Here are the results verses the current times for each line, I have left out Te Mahia and Westfield as based on the draft RPTP they are likely to close, I have however added in the Parnell station. For the Western line I have added in the time allocated for the driver to change ends at Newmarket together with the travel time. You may also notice some of the times look longer than current. That is because AT obviously round the times up or down to get to an exact minute.
As for how much time is saved, well the western line ends up being 3-4 minutes quicker for a trip to Swanson, the Southern a massive 7 minutes quicker out to Papakura, its 3-4 minutes quicker to both Manukau and Onehunga. The big reason the western line doesn’t gain much compared to the other lines is that it has a lot of really closely spaced stops which continue to slow things down, there also aren’t any plans to drop any stations along the route like is expected to happen down south.
Edit: Here is an image I was working on to show the cumulative time from Britomart which also highlights just how close many of the inner western line stations are to each other