While it’s most likely that we are at least 10-15 years away from seriously considering starting construction of any railway line to the North Shore, given that at its city end the line will need to link into the rest of the railway network in one way or another (either directly or by way of a transfer), there are a matters which need consideration in the relatively near future. Particularly when we’re thinking about the detailed design of the City Rail Link.
My most recent concept for the first stage of North Shore Rail, largely designed as a cheaper alternative to a road crossing, suggests linking in with the rail network at Aotea Station, but probably by way of a transfer, rather than with a direct track connection:
The map below gives a way that this could work in the much longer term, with the North Shore line linking through to the Eastern and then potentially out to the far southeast along this alignment. For the first stage though, it has seemed to me that there’s no reason why the red line couldn’t simply terminate at Aotea station, with people transferring onto “green line” and “blue line” trains to travel elsewhere in the region. Another possible option (although cost-prohibitive in my opinion), might be to eventually link the North Shore Line through to the southern at Newmarket: The route in the map above was used by NZTA to discredit North Shore rail as mind-bogglingly expensive, which obviously it would be with the cross-town tunnel proposed. Other options over the years have included connecting straight into Britomart, effectively forming a “Y” junction underneath the current downtown shopping centre.
Interestingly though, one map in the City Centre Master Plan suggests an alternative alignment:
A number of trains from say the Southern line entering the city via Newton-K Rd would turn west after Aotea station to Gaunt St then head under the harbour to Akoranga and Takapuna. As per your NS programme. Then return back across the harbour, to Gaunt St and continue on to Britomart and then either the Eastern or Southern lines back south. This deals with the capacity issues as it could run without really adding trains to the network, the new line being so short. Direct travelers won’t need to wait long for the next train on the CRL that isn’t heading out to Takapuna, as you wouldn’t run every train this way…
…Gaunt St is going to be as least as important a destination as Britomart at the morning peak with all the offices moving there, and I see no problem with people from the south either transferring at Aotea or Newmarket, or walking from Aotea to get to the downtown area. And many will probably be keen on the one-seat ride directly to the Wynyard wharf area, not to mention Akoranga and Takapuna, from south and east AK. Really from the south if you are heading to Britomart or of course Parnell you’ll change at Newmarket.
It also should mean fewer transfers at the city stations for Shore people, many of whom will have already changed at Akoranga, which would be a good thing. This could also offer one seat rides to the Airport for Shore train riders too.
The possibility of running direct services from Takapuna to the Airport is obviously quite attractive, and I am also mindful that probably most passengers on a North Shore Line that started at Takapuna would have already transferred once between services (from the bus to the train at Akoranga). These are strong arguments for connecting the North Shore tracks into the City Rail Link tunnel directly. On the other hand, if we are thinking about the pure capacity of the system, with the North Shore Line likely to require pretty high frequency trains to deal with its volumes, linking it into the rest of the network could create problems in the long run with too many trains on the City Rail Link tunnel and with it becoming too difficult to manage those trains coming in from various lines, trains stopping at Aotea Station and so forth.
I really don’t know the answer to this issue, but I think it’s something that needs to be given some strong consideration as we shift into undertaking detailed design of the City Rail Link tunnel – because whichever option we choose, if we don’t think about how North Shore rail will ‘link in’, doing so in the future will become much harder and much more expensive.