For buildings and factories located near railway or subway lines, the vibrations caused by the moving trains, especially at high speeds, may be annoying to the residents or detrimental to the high-precision production lines. However, there is a lack of simple and efficient tools for dealing with the kind of environmental vibrations, concerning simulation of the radiation of infinite boundaries; irregularities in soils, buildings and wave barriers; and dynamic properties of the moving vehicles. This book is intended to fill such a gap.Compared with the boundary element method (BEM) for solving the half-space problems, the finite/infinite element method (FIEM) presented in this book has the following advantages: • It requires less effort in formulation and computation.• It can be directly incorporated in an existing FEM analysis program.• It is capable of simulating the irregularities in buildings, soils and tunnels.• It can be used to evaluate the efficiency of various wave barriers for vibration reduction.The methodology presented in the book can be adopted to analyze the vibrations caused by road traffic as well.