Wairarapa Line grind has a long way to go yet

Commuters catching the Wairarapa Line may have to wait for another four months before the track’s bad vibrations are dealt with and until next year for speed restrictions to be completely lifted.

Issues have been caused by new railway tracks installed from the Remutaka Tunnel to Masterton that were, on average, 4mm narrower, resulting in the wheels of the old carriages vibrating on the new track, as they do not have the levels of vibration absorption that other carriages used in the Greater Wellington area do.

It has also meant that trains have not been able to run at their top speed of 100kmh and have been restricted to between 60-70kmh in places to reduce the impact of carriage vibrations.

Following the completion of an independent investigation, KiwiRail and Greater Wellington Regional decided the solutions were to grind the rails and reprofile the carriage wheels.

The twofold solution “could stretch into August” for the 35km Featherston and Masterton phase, KiwiRail metros general manager Jon Knight told the Times-Age.

“We’re aiming to have the work complete by the end of July,” he said.

Knight said that 15 kilometres have been completed and grinding work is being done in the Dalefield area.

The grinding team, which covers between 1km and 1.5km each night, has been working six nightshifts in a row between the hours of 11pm and 3am, he said.

“Greater Wellington Regional Council’s [GWRC] early testing is showing that the track grinding has reduced vibration at the lower speed of 60kmh.”

“However, track grinding by itself is not a fix and won’t result in a permanent improvement, so GWRC, which owns the train carriages, is also reprofiling the train wheels.”

In the second phase, the grinder will head south to complete the 9km Remutaka Tunnel and Featherston sections.

“We’ll complete grinding work on the entire length of line, which is close to 40km,” he said.

“Grinding is part and parcel with line maintenance and costs are all part of the overall maintenance budget.

“Four carriages have been reprofiled and are ready for further testing. Once results are back, further carriages will be reprofiled.”

Knight said that GWRC expects the wheel grinding work will be complete by October.

“The main reason for speed restrictions is getting the line ready for the arrival of GWRC’s new hybrid trains in 2029,” he said.

“These trains will run more often, giving people more travel options, and our work will mean they can travel faster.

“The tricky thing is we need to do this upgrade work now, which impacts on trains running on the Wairarapa Line.

“The Remutaka Tunnel has had a 60kph restriction for the past five years to minimise wear and tear on its aged infrastructure.

“We’re working on replacing the track inside the tunnel now and expect to have the whole job finished by early 2025.”