Author(s): Byrne Stephen
Luas is Dublin’s modern light rail system. Similar to the majority of urban electrical tramways, the system is relatively quiet when compared to diesel locomotives with similar power output. However, electrical rail systems do produce airborne noise. The principle source is the interaction of the wheels with the rails; termed “rolling noise”. Rail roughness, including corrugation, has a substantial influence on rolling noise. To remove rail roughness the rails are ground. To investigate grinding on the network pre- and post-rail grinding, noise measurement surveys were undertaken at eight locations on the network, subject to a rail grinding programme in May 2016. Noise surveys were undertaken monthly from January/February 2016 to October/November 2017 to capture both pre and post-rail grinding noise emissions. Monitoring was undertaken at different track forms (embedded, embedded grass and traditional slab track) with trams passing at different speeds (30–70km/hr). Control locations, not subject to rail grinding, were also monitored. This paper details the results at two locations with embedded and embedded grass track forms. The grinding campaign was successful with reductions of 4.8dB (LAeq,Tp) achieved at both locations. In specific one third octave bands, reductions of up to 13.5dB were achieved. At both locations reductions achieved have largely remained over the monitoring period. However, increases in noise emissions at one of the locations (Location 7) in October and November 2017 indicate that rail grinding may be again required within the next six to twelve months.
Name: Mr Stephen Byrne