A half-billion dollar project to improve the infrastructure and reliability of Wellington's rail network is now two-thirds completed.
The upgrade has been underway since August 2008.
The work includes installing a third main line into Wellington Station and will allow a new fleet of trains to run on the network, which carries close to 200,000 passengers a week.
Project Director David Gordon says the bulk of the physical work is now out of the way but many small jobs remain, including upgrading electrical substations.
Mr Gordon says the project remains on budget and on schedule to be completed by June 2011.
The fleet of new electric trains, which has cost about $230 million, is due to arrive later this year.