A new framework is proposed for analyzing vehicle-bridge/track system dynamical interaction. This framework is based on mode superposition and pseudo force iteration. Both the finite element(FE) models of vehicles and bridge/track structures are established separately by universal software, through which the eigenvalue analysis is carried out to get corresponding eigenvalues and eigenvectors. So motion differential equations of these vehicle and bridge/track models can be set up using mode superposition method. This leads to less effort to form equations of motion for vehicles and less computing time to solve the system responses. Together with mode superposition method, pseudo force iteration method is utilized to handle non-proportional damping, material nonlinearity problem as well as wheel-rail contact relationship. Owing to the iterative method, two kinds of wheel-rail contact condition, i.e. no-jump condition and jump condition, are easily compatible in this framework. The versatility of this framework rests with its compatibility for arbitrary vehicle types, arbitrary bridge-track elements, almost most material nonlinearity and optional wheel-rail contract condition.