RAILROAD NOISE IN AN OPEN SPACE

The model presented here allows prediction of the sound exposure level (L(AE)) and the rime-average sound level (L(AeqT)) of noise, generate d by trains moving with a steady speed in an open space, The receiver is assumed to be so close to the track that geometrical spreading is e ffected principally by the ground effect. A real train is modeled by a homogeneous line of point sources with dipole directivity. To fit the time asymmetry of the time history of noise level which is produced b y a high-speed train, a 'virtual source' has been introduced. The free parameters of the model can be estimated from two simultaneous measur ements of L(AE) at distances of D-0 and 2D(0), respectively. (C) 1997 Elsevier Science Ltd.