The regional council hopes the horrendous noise problems on the Johnsonville line will be solved before a planned timetable overhaul comes into effect.
However, with the changes planned for 2020, the noise may not be fixed any time soon.
This year, Greater Wellington Regional Council and KiwiRail will continue to try to find the solution to the loud screeching noise made by the Matangi trains.
The noise has been a problem since the trains were introduced on the line in 2012.
At various points along the line, the train wheels make a high- pitched squeal, which is caused by the way the wheels interact with the top of the inside rail.
Trials of solutions to the noise took place throughout 2013, but a screech-free area seems no closer than it was at the last public meeting, in June.
However, regional council rail operations manager Angus Gabara said signs were hopeful.
"The three friction modification machines are all operating and recent results are encouraging."
"Spikes in noise occur when the friction modification machines are not fully functional, and maintaining these is now part of our track agreement with KiwiRail."
Gabara said the costs of the trials were still to be determined.
The proposed changes to rush- hour timetables would mean more trains on the Johnsonville line, and from Taita and Porirua, during peak times.
Four services an hour are planned to depart from Porirua and Johnsonville between 7am and 9am, and five an hour from Taita, although that number could double, depending on demand.
The proposed system would be made possible by the arrival of 35 more Matangi trains by 2016.
The new trains will be fitted with wheel dampers, one of the solutions being used on the Johnsonville line to control noise.
The regional council hoped the noise problems would be solved by the time services were increased in 2020, Gabara said.
The next step in the trials is to complete a wheel-to-rail interface study.
That will determine whether a different wheel or rail shape would help prevent the wheel squeal.
Have you noticed a change in the noise made by the Matangi trains on the Johnsonville line? Has the noise decreased or increased? Write to us at email@example.com.
March 2012: Matangi trains introduced on Johnsonville line.
June 2012: Source of noise identified.
September 2012: Two solutions identified: wheel dampers and friction modification.
October 2012: Prototype wheel damper developed.
November 2012: First trial of friction modification and automatic applicators ordered.
July 2013: Rail grinder re-surfaces the track.
March 2014: Three friction modification applicators operating on the line.
Next steps: Analyse the shape of the rail to find out if changes would reduce noise.
- The Wellingtonian