Media release from Greater Wellington Regional Council

18 March 2013

Wheel dampers next step towards reducing wheel squeal noise on Johnsonville Line

A trial of wheel dampers, which reduce noise radiation, on two trains next month is the next step towards trying to reduce the wheel squeal noise on parts of the Johnsonville Line, says Fran Wilde, Chair of Greater Wellington Regional Council.

The noise emerged after the new Matangi trains began running regularly on the Johnsonville Line just on a year ago.

The squealing noise is created when the wheels of the train manoeuvre through some tight corners. “The old English Electrics that used to run on the line generated more noise but it is the high-pitched tone of this particular noise that is literally getting on some people’s nerves.

“Wheel squeal issues are not uncommon on rail lines around the world, so we were able to engage some rail experts experienced with these issues. They investigated the exact cause of the problem and developed a range of possible solutions for us. We’re now trialling the two top solutions.”

Fran Wilde says over the last few months a friction modifier material has begun to be applied to the track on some parts of the line to modify the steering performance of the wheel sets on tight curves. The material is then distributed, via the wheels of the train, further along the line. “This is having varying levels of success – some trains are less noisy but others aren’t. Staff are currently investigating ways to increase coverage of the friction modifier to reduce the noise all along the line.”

From next month wheel dampers - devices that reduce the radiation of noise - will be trialled on the wheels of two trains.

“Hopefully the greater spread of friction modifier on the track and the effect of the wheel dampers should significantly reduce noise levels.

“I appreciate the distress the wheel squeal noise is causing to some residents who have to put up with the noise day in and day out, but I can assure them that this is the number one priority for our rail operations staff and they are determined to find a lasting and effective resolution to this issue.”

Regional Council and KiwiRail staff will give a full update to residents at a public meeting at Ngaio Town Hall on Wednesday evening at 7.30pm.

ENDS

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