Auckland Transport have released a previously confidential board paper – that’s surprisingly short on detail – behind their decision to only build the Mercury Lane entrance to the Karangahape Rd Station instead of also building one at Beresford Square. In total the change is expected to save around $30-40 million.
The report states that while the station has always been shown to have two entrances they only ever intended on building one initially. When and why that decision was made is unknown – I assume as a way to save costs and perhaps stemming from the time when they were trying to get out of building the station altogether. They go on to say that a single entrance will be enough to cope with expected demand to the area out to beyond 2046 which is likely where their projections end. It’s this kind of statement that raises flags with me as it suggests the level of demand is some kind of pre-determined outcome rather than a response to what’s built.
It has always been assumed that the Beresford Square entrance would be the primary one however AT say that while working on the reference design for the station a “value engineering initiative” identified the option of changing the order around.
Other than the cost saving two of the key reasons highlighted as justifying the change are
- That there is a lot of potential for development around the station entrance.
- That it would be more difficult to get the space needed to dig out the Mercury Rd entrance at a later time while they say this can be done at Beresford with “relative ease”
Starting with a base design of building the Beresford Square entrance the engineers then came up with six options for the entrance
- Option 1A a value engineered option of option 1 where Beresford Square is constructed first with vent and escape stair in widened footway in Pitt Street future proofing for Mercury Lane.
- Option 1B as option 1A but with no future proofing for Mercury Lane.
- Option 2A Mercury Lane entrance constructed first with vent and escape stair in Pitt Street with future proofing for Beresford Square entrance.
- Option 2B as for 2A but with vent in a median in Pitt Street and escape stair in Beresford Square
- Option 3A as for 2A with no future proofing for Beresford Square.
- Option 3B as for option 2B with no future proofing for Beresford Square.
To identify what is the best option they conducted a multi-criteria analysis, the results of which are below. The two cost metrics seem to have a set score out of five but for the other criteria it appears they have averaged the score of different members of the CRL design team.
The results show that options 1A and 2A have the best scores when you ignore the cost criteria however options 2A and 2B perform better when the cost is added in.
The next table takes each areas and doubles the rankings in each area in a separate test to see how the results change.
When you look at the the results with costs added option 2A comes out on top which is the option they have gone for.
There are a few other comments in the report that are interesting/odd.
The Cross Street link between the LRT proposal in Queen Street and the CRL station entrance in Mercury Lane provides part of an integrated public transport solution for the precinct.
Cross Street has been identified for providing a shared space environment encouraging pedestrians to use this link between the CRL entrance in Mercury Lane and the LRT stop at the top of Queen Street
It’s odd that they talk about using Cross St as a link between the CRL and LRT stations being as part of an integrated PT solution but seem to ignore any idea of integration with buses – which would be much easier with a Beresford Square entrance. Cross St is also a place that would need a lot of private sector investment to make a shared space really work.
A few people in recent posts about the images have commented on the grade of Mercury Lane, this is what is said about it.
The gradient of Mercury Lane has been raised as a potential issue. The current gradient varies between 1 in 9 and 1 in 13 between Karangahape Rd and the station entrance. This gradient is no worse than the gradient of Victoria Street and Wellesley Street from Queen Street to the location of the station entrances to the CRL Aotea Station.
Lastly it seems one of the justifications for the change is a claim that the patronage catchments have been raised. This appears to be based simply on looking at the coverage of some concentric rings shown around the station (below). For a project of this size it seems like an awfully simplistic measure. If you gave the image below to someone who didn’t know anything about Auckland or the CRL they’d probably question why even both with the Aotea Station even though it is forecast to be the busiest on the network. Each of the stations have quite different pedestrian catchments and it seems odd they didn’t take walking viability into account.
The potential change to the patronage catchment areas to the CRL has been raised. If adopted, the Mercury Lane entrance increases the distance between Aotea Station entrance and Karangahape Station entrance by approximately 200m and reduces the distance between Karangahape station entrance and Mt Eden station entrance by 200m. The overlap in 800m and 1200m catchment rings are shown in attachment 2 to this paper.
It may be better than no station at all but I remain unconvinced of having a single entrance down in Mercury Lane. In my view build the station once and build it right, with both entrances.