As dignitaries waited patiently on the platform, a historic train rolled into Onehunga's new railway station yesterday - ominously, about an hour late.

Nineteenth century technology met 21st century transport problems head-on when the long-awaited steam train arrived to mark the reopening of a 3.6km passenger line - a key addition to Auckland's public transport network.

And on Friday, dignitaries will again troop out, to the opening of the New Lynn interchange, where the double-tracked western railway line has been "trenched" to separate rail from road, and ease congestion.

The Onehunga line opens for paying commuters today - 37 years after the last passengers caught the train in Onehunga, and long after the line carried its first train in 1873.

With 49 services operating every weekday, the trip between Onehunga and downtown Auckland will take only 25 minutes. At least, that's the plan. But yesterday's omens were hardly propitious.

Auckland Regional Council chairman Mike Lee, a long-time proponent of reopening the Onehunga line to passengers, said the huge turnout yesterday indicated a seachange in the way Aucklanders viewed rail passenger transport.

Referring to the Onehunga and New Lynn rail developments, he said people would look back on September 2010 as the day the phrase "Aucklanders never get out of their cars" lost its meaning.

Transport Minister Steven Joyce said the developments were a step towards Auckland becoming an "efficient and prosperous world class city".

New network-wide timetables began yesterday, with more than 400 extra train trips a week across Auckland, about a 25 per cent increase in services according to ARTA chairman Rabin Rabindran.

$13.6 million investment
* Auckland Regional Transport Authority spent $3.6 million on the Onehunga line including three new stations at Penrose, Te Papapa and Onehunga.

* Penrose and Te Papapa platforms are 90m long; Onehunga is 54m long - meaning the platform will have to be extended to serve the new electric trains being introduced in 2013.

* Each train on the line will have capacity for about 132 seated passengers or 250 people per two-carriage train.

* KiwiRail spent $10m rehabilitating the track.

* The authority expects 500 passengers to use the Onehunga line every week day.