Abstract. We consider model order reduction of mechanical systems with moving loads. Such systems have a time-varying input matrix that makes it difficult the direct application of standard model reduction methods. In this paper, we present a two-step model reduction approach for systems with moving loads which is based on a low-rank approximation of the input matrix and applying Krylov subspace methods to the resulting linear time-invariant system with a modified input. Numerical results demonstrate the properties of the proposed model reduction method.Key words. mechanical systems, moving loads, model reduction 1. Introduction. In structural dynamics, the moving load problem has received a lot of attention because of its importance in many practical applications. Mechanical systems with moving loads arise, for example, in modelling of bridges with moving vehicles [17,32], cableways [17], cranes [42] or working gears [39]. One of the most popular methods for simulation of the dynamic behaviour of such systems is a finite element method (FEM) based on a variational formulation of the structural mechanics problem, e.g., [41]. In the engineering literature, the principle of virtual work is used to derive the FEM approximations, see [5]. The FEM discretization of a system subjected to moving loads yields a linear time-varying (LTV) second-order system