Abstract: To study more and more serious vibrations problem induced by moving train traffic in urban areas, in a residential district near Jing-Guang Railway, field tests of velocity and acceleration vibrations of ground were carried out during train moving; and some conclusions were drawn. It is shown that the vibrations of ground due to moving train rise with train speed or axle load increasing. Generally, when speed of train increases 10 km per hour, the vibrations level raises 3 dB, while at the same speed, vibration induced by freight train is bigger than passenger train because of the difference of axle load. In the test, at speed of 50 km per hour or so, the vertical velocity vibration induced by freight train is about 10 dB bigger than that of passenger train, and as for the difference of lateral velocity vibration, this magnitude is about 5 to 15 dB; moreover, as for the difference of vertical and lateral acceleration vibrations, they are 12 dB and 8 dB respectively. The vertical velocity vibration of ground near the joints of rails is 2 to 6 dB bigger than the other positions far from joints. Ground vibration decreases gradually with increasing in the distance between testing locations and rail; and there is a fluctuated characteristic of the decay process for vertical vibrations; while the lateral vibration decreases monotonically with increasing in the distance between testing locations and rail.

Key words: train, ground, vibrations, field experiments