Professor Chris Jones
University of Southampton, UK
Railway operations produce vibrations propagating in the ground which can
be perceptible at properties near to the line. This is perceived in two
ways, each of which are significant problems for railway engineers to
tackle.
At frequencies in the range of about 30 Hz to 200 Hz vibration transmitted
to buildings excite bending waves in the floors, walls and windows that
then radiate as structure-borne or 'ground-borne' noise directly into the
rooms. This is usually only perceptible in buildings above covered
cuttings or tunnels where the air-borne noise of thd medium together with suitable models of the
track. Some results of the prediction of vibration from trains using the
model are compared with measured vibration for different cases. These
provide answers to two questions that railway engineers have been asking
for a long time.
Which is the more important source of vibration poor track
geometry or the time history of axles passing by?
What will happen if the train speed is increased beyond the speed
of waves in the ground?
