A central device includes an information replacing unit. When the information replacing unit detects, on the basis of contact information acquired from an electric coupler provided in a coupled vehicle in a formation B having a train-information management device that manages vehicle information in accordance with the Ethernet® protocol, that a formation A that includes a train-information management device that manages vehicle information in accordance with the ARCNET protocol is coupled to the formation B, then the information replacing unit replaces vehicle information from the formation A with vehicle information in accordance with the Ethernet® protocol; outputs the replaced vehicle information to the formation B; replaces the vehicle information from the formation B with the vehicle information in accordance with the ARCNET protocol; and outputs the replaced vehicle information to the formation A.