This paper deals with response analysis of inelastic simple engineering structures under high-speed train-induced vibration. The dynamic load is represented as a time-variant pulse-train function of unequal amplitudes. The structural response is quantified in terms of ductility factor, permanent deformation, number of cyclic loops, and input, hysteretic and damping energies. Measures of the structural performance based on energy concepts and damage indices are also considered. Specifically, the structural performance is quantified in terms of Park and Ang damage index. Damage indices imply that the structure is damaged by a combination of repeated stress reversals and high-stress excursions. In fact, the use of damage indices provides a measure on the structural damage level and required repair. A new scalar index based on Park and Ang and Cosenza and Fajfar damage indices is also proposed in this paper. The formulation is demonstrated by studying the structural response of single-degree-of-freedom inelastic structure to pulse train load composed of locomotive and 10 coaches. A computational code is developed in the Matlab platform to illustrate the numerical results.