Last big summer shutdown puts finishing touches to network, and new trains are on target for April next year.
Auckland's $1.14 billion rail electrification project is chugging into the home straight, ready for the arrival in September of the first of 57 zippier and quieter trains.
KiwiRail is using its last big summer shutdown of the region's rail network to rearrange tracks at Britomart and two other locations before spinning the final segments of an electrical web which by August will cover about 85km of lines from central Auckland to Papakura in the south and Swanson in the northwest.
It is enlarging the "throat" between Britomart's approach tunnel and the underground station's five platforms for extra train crossover points to be installed in a four-week shutdown of the eastern and Newmarket lines, and has been laying new bypass tracks at Otahuhu and Papakura during a two-week region-wide closure to minimise conflicts between freight and increased passenger services on an electrified network.
The state-owned company has also been taking advantage of the shutdown since Christmas, during which buses have replaced trains, to string electric lines on masts already erected between Papakura and Otahuhu on the southern line.
Signal systems on most of the rail network have been modified so electric trains can run at 10-minute intervals in each direction, and about 60 per cent of the overhead wiring should be installed by the end of this month.
KiwiRail has finished raising 24 road and pedestrian bridges over the rail network to fit electric wires under them, and is installing protective screens on those and 63 others to ensure people do not accidentally come into contact with the 25,000 volts of alternating current which will power the new trains.
Meanwhile, at a factory in northern Spain's mountainous Basque region, assembly of the shell of the three-car electric trains will begin this month.
Tests start separately on its propulsion system before the parts are put together and shipped to Auckland for a rigorous commissioning between September and Christmas.
The first of two driving-cab simulators is due in May, so rail operator Veolia can prepare its staff for a flying start once the trains arrive.
A third big piece of the jigsaw, a $96 million maintenance and stabling depot, is taking shape under Auckland Transport's auspices at a former quarry site beside the main trunk line at Wiri, ready to keep the trains in top condition for the extra passengers needed to meet ambitious public transport growth targets.
By this time next year, nine trains should be being prepared to carry their first fare-paying passengers between Onehunga and Britomart in April along tracks which have already been electrified.
At that point, two new trains should be arriving each month from Spanish manufacturer CAF until October next year, when the delivery rate is to double to meet a final delivery deadline of mid-2015 for the fleet.
Mayor Len Brown says the arrival of the trains will be "a huge step on the path towards the kind of integrated transport system an international city like Auckland needs".
He believes the electric units - which will have greater acceleration and braking power than the existing diesel fleet - will make rail patronage "rocket" and create even more pressure for a 3.5km underground rail extension from Britomart to Mt Eden.
But council transport chairman and veteran electrification campaigner Mike Lee believes the new trains will not be enough to boost flagging patronage unless they are supported by general service improvements, notably far better punctuality and extended weekend timetables, without prohibitive fare rises.
"I would not bank on electric trains in themselves fixing chronic underlying human management problems," he said.
Although he was preparing to pop champagne corks last year in expectation of overtaking Wellington's annual rail patronage of 11.3 million passenger trips, he is bitterly disappointed by a fall from a record 10.98 million trips in Auckland for the 12 months to April - a figure boosted by the 2011 Rugby World Cup - to little over 10 million by November.
That compares with 63 million trips taken in Perth last year, up from about eight million before that city switched to electric trains in the early 1990s, when it sold its diesel units to Auckland.
Mr Lee said it took a concerted campaign by the former Auckland Regional Council, which he chaired, to convince Labour Finance Minister Michael Cullen in 2008 to support electrification on the basis that "rail would go onwards and upwards forever in Auckland".
It was ironic that the "kicker" argument for electric trains was that the underground rail extension could not be built without them, yet Auckland was now having trouble convincing the Government of that project's merits.
But Mr Lee believes an extension of the electrification project to include electric locomotives could boost the economic case for a rail tunnel, by enabling Auckland to retain some of its rolling stock without having to buy a second fleet of new trains in addition to the 57 on order.
He is annoyed Auckland Transport has included more than $300 million of extra trains in an inflation-adjusted cost estimate of $2.86 billion, resulting in a predicted return of only 90c for every dollar invested in a new rail tunnel, and says that without them the project would more than break even.
That could be achieved by using electric locomotives to haul existing passenger carriages by day, and freight to and from the port at night, reducing emissions and noise through residential suburbs.
On the way
* 57 three-car trains arriving between September this year and mid-2015.
* Tracks, signals, and other works such as raising bridges over 85km of lines from Britomart to Papakura and to Swanson - $500 million cost (Government funded).
* Trains and depot (including 12-year maintenance contract) - $640 million (cost shared between Government and Auckland Council).