A wideband multiple tuned mass dampers (MTMD) system has been developed for reducing the multiple resonant responses of continuous truss bridges to moving train loads. This system is composed of several MTMD subsystems, each of which consists of one set of TMD units covering a specific frequency bandwidth, but with its medium tuned to one of the first few resonant frequencies of the bridge. Using the minimum–maximum amplitude criterion and enforcing the resonant peaks of interest to be equal to each other, one can determine the mass allocated for each subsystem, as well as the optimum parameters. If there is a concern over detuning of the target frequency with the structural frequency, it is suggested that the bandwidth of the MTMD system be widened accordingly. In this study, the train-induced response of a truss bridge installed with the wideband MTMD system was analyzed, by which the robustness of the proposed method in vibration reduction was demonstrated.