This chapter presents the key acoustical terms commonly used in descriptions of noise and vibration environments. It summarizes the noise and vibration characteristics of high speed rail/maglev systems. The chapter provides the criteria used to assess noise and vibration impacts in various countries and demonstrates an approach for assessing impact. It then discusses countermeasures against noise and vibration from high speed rail/maglev systems. Noise from a high speed rail system is generally dominated by three sources: the propulsion and auxiliary equipment, mechanical/structural radiation and airflow moving past the train. High speed trains are generally electrically powered; the propulsion noise sources are those from electric traction motors or electromagnets, control units and associated cooling fans. Noise assessment for a new high speed rail project is performed in three stages as the project develops. In the early planning stage, a Screening Procedure is used to determine whether any noise-sensitive receivers are within a distance where impact is likely to occur.