Diss. Stockholm : KTH. Royal Institute of Technology. Department of Vehicle Engineering, 2001

Railway track and ground vibrations are considered, with an emphasis on methods of mitigation ("countermeasures"), for application to wayside disturbance problems. Original field measurements from two sites in Sweden, as well as borrowed measurements from Norway, provide vibration results at many points on the track, on and underneath the ground surface, for a variety of trains, both with and without countermeasures in-place. Infinite periodic system theory is the basis of track-only and track-ground interaction models presented. The repeating element includes the sleeper, pad-fastener, rail, and either a locally-reacting ballast or a continuous ballast-soil waveguide. The track-only model is even refined for nonlinear and high-frequency cases. The models are suitable for studying countermeasures in the track, or in the foundation (soil-stabilization). This latter countermeasure is shown to be effective at low frequencies (of geotechnical interest), but sometimes counterproductive at audible frequencies (disturbance problems). An analytical model for hard seismic screens is also presented, to complement the treatment of ground vibration countermeasures; this is based on physical approximations which are favored by "high" (i.e, audible) frequencies and soft soils. Notably, experimentally observed resonant behavior is explained.