ABSTRACT
Measurements were made under traffic of track deflections and of movement in the ground beneath railway track at an embankment which suffered chronically from rapidly deteriorating track geometry and from the need frequently to deposit ballast on the track. This chapter presents some measurements of vibration on track and in a railway embankment which were undertaken to help understand why the track structure was unstable, with frequent tamping and deposition of ballast being required in order to maintain satisfactory line and level. Accelerations were measured vertically on the rail, on a sleeper and within the embankment under traffic. A classical beam-on-elastic-foundation analysis indicates that the observed behaviour is consistent with calculations for track with a modulus of 1.0MPa or less. The most important consequence of this behaviour for present purposes is that it helps not only to explain the problem of maintaining satisfactory track geometry at the site but also to suggest possible solutions to the problem.
