Experimental evaluation and numerical interpretation of various noise mitigation strategies for in-service elevated suburban rail

This research evaluates the efficiency of five noise mitigation measures including rubber floating slab track, straight noise barrier, track acoustic absorber, track-side noise barrier, semi-closed noise barrier, and a combined strategy on an elevated railway through in-situ measurements. In-situ experiments were conducted by sequen- tially installing various mitigation measures for comparative evaluation. A numerical model was then developed to interpret the noise control characteristics of the mitigation measures. The experimental results indicate that the rubber floating slab track can mitigate bridge-borne noise by 0-4 dB sound pressure level (SPL); the track acoustic absorber can mitigate the railway noise by 3–5 dB(A) and its combination with track-side noise barrier boosts the insertion losses of SPL by 2–7 dB(A). The combined control strategy shows overall better performance than individual mitigation measures within the efficient noise reduction regions. The experimental and nu- merical results can serve as a guide on the design of noise control strategies for elevated railways.