The Bridge's Clickety-clack To Be Stilled

Sydney Morning Herald

Wednesday April 26, 1995

By JAMES WOODFORD Environment Writer

The deafening groan of trains lurching across the Harbour Bridge is one of Sydney's most famous noises. But soon the clickety-clack will disappear forever.

From this weekend, thousands of 26-kilogram unbreakable "eggs" - made of rubber with a cast-iron yolk - will be placed under the tracks to cushion the noise and bring peace and quiet to Sydney Harbour.

The rubber in the "Cologne Eggs" moves up and down by half a centimetre and absorbs vibrations.

Every few minutes for more than 20 hours a day, all noises within coo-ee of the bridge - ferry horns, the screams from Luna Park's big dipper and the hustle and bustle of The Rocks - are drowned out by trains making the journey between Wynyard Tunnel and Milsons Point.

Noise levels from the "bell effect" caused by steel wheels rolling over the steel bridge have been measured at up to 90 decibels.

Long-term exposure to noise above 80 decibels can cause hearing loss.

The bridge noise is made worse by the clickety-clack sound caused when the tracks have gaps in them.

Mr Kjell Blendulf, the managing director of Delkor Ltd, the manufacturers of the eggs, said that once in place the eggs will require no maintenance and will last for 30 years.

They were designed in Germany and are being manufactured by Delkor under licence.

Eggs are already in place under the Conservatorium of Music, the ANA Hotel and the Theatre Royal, and at the platforms at Circular Quay.

Mr Blendulf acknowledges that the clickety-clack is a familiar sound to Sydneysiders, but says it is one they can do without.

"Everyone that comes to the city (as a tourist) ends up at The Rocks at some stage and you can have much nicer things to listen to than the rattle of trains," said Mr Blendulf.

The first of the eggs will be installed under the 1.1 kilometre of track closer to the roadway this weekend.

In August the second of the two lines will be fitted with eggs. Mr Blendulf estimates that the noise from the trains will be reduced by 50 per cent after the 9,200 eggs have been put in place.

To stop the clickety-clack, CityRail will also replace the discontinuous rails with tracks that are heavier and have been welded together.

Nearly 1,000 wooden sleepers will be replaced and the Roads and Traffic Authority is working on the bridge's girders.

The cost of the noise reduction program will be $6 million and the eggs will cost $2 million.

"The combination of all these things is going to make a significant improvement in comfort levels for people in proximity to the bridge," said a CityRail spokesman.