Extensive mechanical issues and passenger calls for more a more reliable service have forced Tranz Metro to pull trains off the Johnsonville line.
A combination of trains and express bus services in the morning peak will replace the reduced train capacity until Tranz Metro rolls out more Korean-built Matangi 'wind' trains.
Passengers using trains on the line have been plagued by cancellations, delays and disruptions due to landslips, mecahnical problems, staff shortages and derailments over the past year.
Tranz Metro have hailed the Matangi as ''quite simply, the future'' and the new trains will be introduced on the line on March 19.
Usual timetabled services will operate on the Johnsonville line using three trains - one four-car train and two two-car trains - supplementing the 7.46am and 7.58am train services from Johnsonville to Wellington with an express bus.
There will also be an express bus that leaves Crofton Downs at 8am to assist with passenger numbers at that station.
The buses will be express to Wellington, while the trains will make their usual stops.
In addition to the usual train services, these buses will be running at the same time every weekday over the next six weeks.
Tranz Metro manager Scott Brooks said lower passenger numbers on the other services means there would be enough trains to cope with demand.
"However, we will continue to monitor passenger numbers and extra bus services may be required on some occasions to cope with extra demand.''
''We know the disruption Johnsonville commuters have experienced must be frustrating. We are doing the best we can to minimise disruption."
GWRC economic wellbeing committee chairman Peter Glensor said the English Electric trains operating on the Johnsonville line are more than 60 years old and beyond their economic life.
''After years of sterling service, we have had to recently de-commission some of them due to the extent and cost of the mechanical work required. It is simply uneconomical to pay for the repairs, which could run into the hundreds of thousands, only to have them operating on the line for a very short period of time. I'm sure ratepayers would agree that this is not good use of our funds,'' Mr Glensor said.
-The Dominion Post
Which of these best describes your home?Related story: Homes may be making children sick