The Saddle-Profile-Rail - a squeal free rail design

摘要

The squeal noise generating mechanisms has been studied by a non-linear lumped parameter model, It was then revealed that the squeal vibration level in the wheel could be reduced by a reduction of the rail apparent mass. The desired lower apparent mass in the new rail design is achieved by a "saddle-like" profile covering the railhead and which is dynamically decoupled from (at least at squeal frequencies) from the railhead by a thin rubber mat. A 20-m long test section of Saddle-Profile rail has been built in a curve of radius 50-m at a depot track of Stockholm Transport (SL). Narrow band FFT analysis of the recorded sound pressure time history reveal that the sound pressure level at the first and second squeal frequency is reduced by 30-37 dB compared to the squeal sound pressure levels from the adjacent, non-treated, track sections. The wheel/rail curve squeal noise is thus totally abolished by the Suddle-Profile-Rail. The technique has been developed within the BRITE EURAM project SQUEAL (BRPR-CT97-0477) and is protected by two patent applications.