In this study, the distributed cruise control problem of high-speed trains' movements is investigated. Firstly, the problem of a single train with multiple cars is interested, and the aim is focused on the design of a distributed controller, with which the train achieves the safe moving, i.e., all the cars track a desired speed and any neighbouring cars keep a safe distance from each other. By considering, among the cars, the physical coupling structure between each neighbouring cars constitutes a physical connected interaction graph, and by posing the speed information exchange mode that the communication topological graph has a directed spanning tree, a new approach based on the complete consensus technique is proposed to solve the problem. Compared to the existing centralized control scheme or the decentralized control scheme, where the control design of each car need the measurement information (i.e. the displacement and the speed information) of all the cars, the designed distributed control laws have the merit that the control design of each car only uses the measurements of itself and its neighbouring cars; besides, the problems are solved in terms of the purely graphic topological conditions, which are easy to be verified. Then, simulations are provided to illustrate the effectiveness of the obtained theoretical results.