Grease gets quiet on the disturbing wheels squeal – New Technology

     Lubricant on the rail reduces the disturbing noise significantly, shows the study. Photo: Alamy
     

Jet lubricant on the rail so reduces distracting wheel screams significantly. It shows the Swedish Transport Administration’s tests in Södertälje and the Ore Line.

Wheel Shout it tågljud that bothers people most most. The sound having a frequency between 400 Hz and 10 kHz, can occur because of friction wheels against both the outer and the inner rail in curves. Transport Administration has a two-year project tested a new way to reduce the noise with a lubricant that reduces friction. The tests are aimed partly at Malmbanan and in a tight curve in Södertälje.

– The surveys we have done shows that the wheels scream can reduce the up to 13 dB in exposed places, and there is a marked difference, says Matthias Asplund, project manager at the Swedish Transport Administration.

Transport Administration lubricates ago long rail sides in exposed stretches to reduce friction and wear. What is new is that the lubricant is now in place is applied on top of the rail. The challenge is that friction then not be reduced too much because the trains must have left his braking ability.

lubricant must also be electrically conductive. The reason that the railway signal system keeps track of where trains are by measuring the electrical potential between the right and left rail. When a train passes so short wheel axis voltage and the potential difference between the rails disappear. Then know signaling that a train is at a certain distance. The lubricant is therefore contains iron, so that the axles are still shorting the rails.

– We modifies friction without compromising the safety and driveability, says Matthias Asplund .

is applied by using strips with holes that are mounted on the rail, plus a solid lubricating station that stands at the side of the track. Every time a train passes activates a pump that ejects lubricant after every fifth wheel passage. The wheel takes the muck up to five kilometers. In addition to wheels scream decreases, also reduces wear on rails and wheels.

The project is a collaboration between the Swedish Transport Administration, Lulea University of Technology and Railway Research Centre. The lubrication technique called Top of rail and used previously in Canada. In Sweden there are no decisions to start using the method.

– But my guess is that we have 50 such here lubricating stations within a decade, says Matthias Asplund.

The cost he estimates to be around 200,000 to 300,000 per lubrication station in round figures , considerably less than building and maintaining noise barriers. He also says that there are more methods to silence wheels scream, for example by optimizing wheel and rail profile. In an EU project is now evaluated several solutions.

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