The Britomart Problem

I spent about half an hour writing this post last night before my computer decided it wanted to eat it. But I’ll give it another go – perhaps it will turn out better second time around. Who knows.

Anyway, this post is about the Britomart Transport Centre, the hub of Auckland’s rail system. Britomart was opened in July 2003, bringing trains back into the CBD for the first time in over 70 years. Since that time rail patronage in Auckland has really taken off, as people now see catching the train as a far more viable option than before – when the Beach Road station was very much in no-mans land at a far corner of the city centre that wasn’t really within easy walking distance from the main shopping and office areas. So there is no doubt that Britomart has been a big success, that it is the best thing to happen to Auckland’s rail network in well over 50 years and that it can take the credit for a huge revival of Auckland’s public transport fortunes, particularly when it comes to rail patronage.

However, because of the rather fraught and controversial history of Britomart, when it eventually got around to being built a rather half-arse job was done in some respects. The obvious problem with Britomart is that it’s a dead-end station, which means that every train that comes in must leave from the same direction. The other big problem is that all this must be done through a two-track tunnel which links the station to the rest of the rail network to the east. These two problems create a situation where a maximum of only 18 trains per hour can enter and leave Britomart. Even though there are five platforms, the fact that all arriving trains have to travel along one line of track and all leaving trains must travel along the other means some pretty complicated signalling needs to happen to ensure that none of the trains crash into each other as they head from their allotted platform to the necessary track and back up the tunnel (or vice-versa of course). I’m not sure whether the current peak hours schedule 18 trains per hour, but we might be fairly close to that situation and I know that if one little thing goes wrong with the signalling the train systems ends up back in the stone-age with paralysis spreading across the entire network incredibly quickly.

Over the past few weeks, while the train system has been in Christmas shutdown, the tracks at the eastern end of the Britomart tunnel have been getting an important upgrade that will allow both the tracks to become bi-direction (in that trains can enter or leave along either of the two tracks). Apparently this will allow up to 24 trains per hour to come and go from Britomart, a fairly useful increase. I’m certainly no expert, but making both tracks bi-directional means that you put a lot of faith in ensuring that your signalling system is working perfectly, so you don’t end up with head-on collisions or one little fault messing everything up and once again paralysing the rail network almost instantly. The upgraded signalling hasn’t been installed yet, but when it does I guess we can assume that Britomart will have a working maximum capacity of 24 trains per hour.

This should cover us for the next few years. As I said earlier I’m not sure exactly how many trains use the station at current peak hour, but assuming that ARTA’s goal of 10 minute frequencies comes to fruition in the next few years that would equate to 18 tph if the three lines are combined. Add in a few Onehunga/Helensville/Hamilton services that may come on board in the next few years and we’re getting pretty close to that 24 tph limit. Furthermore, it is really highly debatable whether 10 minute frequencies are going to be high enough – not so much to create a good level of service (which a train every 10 minutes possibly is, especially for Auckland) – but largely because I don’t think that will be enough trains to cope with patronage increases. Assuming that current low petrol prices are the exception and not the norm, that electrification improves the perception of the rail network tremendously and that integrated ticketing makes it much easier for people to catch feeder buses to train stations, I think it’s quite conceivable that rail patronage could at least double by 2015 from where it is now. Last winter, with petrol prices skyrocketing, trains became unbearably overcrowded (although this was partly due to stupid train allocation). With a doubling of patronage by 2015 I don’t think 10 minute frequencies on the three main lines will be sufficient. But putting aside the question of ‘will we have enough trains’, how long is it going to be until we hit that 24 tph Britomart capacity?

ONTRACK, the government agency that owns the tracks, reckons this will probably start to become a problem around 2015 – which fits in quite well with my estimates. So what are the options for relieving this? Well in my opinion there are two options (or three, as “doing them both” is probably necessary in the long term).

1. Build the CBD loop tunnel
2. Duplicate the rail tunnel into Britomart

Building the CBD loop tunnel is definitely the ‘prefered option’ of the two above. This would turn Britomart into a through station (for at least the outside two platforms) which would certainly relieve things as trains wouldn’t have to come back along the same way they arrived. With most trains continuing through Britomart (either clockwise or anti-clockwise around the loop) an in-movement effectively also becomes an out-movement and the same in the opposite direction, so effectively the capacity is doubled (although probably a bit less as not all 5 platforms will be continued straight ahead.

Having given it a bit more thought, and with a bit of help from various people on the Better Transport Forum, here’s how I think the services through the loop should operate:

The way this would work is dependent upon a fourth ‘Airport’ line being created. Ideally this line could continue from the airport through to the NIMT around Puhinui, and become the main inter-city line (so that people from other parts of New Zealand could easily catch a train to Auckland airport without having to go via Britomart). But anyway, the current three lines that Auckland operates is upgraded to make four lines: the Western Line, the Southern Line, the Eastern Line and the new Airport Line. The four lines are ‘paired together’ to create effectively two lines, each of which travels around the CBD loop. This would lead to a significant number of trains travelling around the loop, which is obviously desirable, and would also shorten the trip from the Western Line into the city quite significantly, as the trains would not have to loop all the way around via Newmarket anymore.

A couple of minor disadvantages emerge from this. The first is that people wanting to get to Newmarket from the West have their trip lengthened, as they would have to go via the CBD loop and Britomart. To me this isn’t really a biggie as I reckon more people from the West want to travel to the city, so the time savings there more than make up for the time-loss by the longer trip to Newmarket. The other problem is slightly more significant, in that Boston Road station is no longer served by the Western Line at all, so to get there from the west you’d have to transfer at Mt Eden. That seems highly possible, and is possibly outweighed by the fact that Boston Road is now easily reachable from both the south (via the Airport Line) and the east than it ever was before. Once again, this is possibly more of a gain than a loss.

The big disadvantage of the CBD loop is its cost, which seemed to be going up all the time. When I first hea
rd about this project the estimated cost was around $500 million, whereas now it is 2-3 times as much. The other problem is how long it will take to build, even assuming that the cost can be covered. It’s not likely to be operational for at least another 10 years, which means that the capacity constraints of Britomart will be reached before that time.

Which brings us back to option 2, duplicating the Britomart tunnel. I’ll talk about that next time.

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