Departing from the present situation, this paper attempts to highlight future prospects of high-speed railways. A panorama of high-speed lines worldwide is first given and the limits of a further increase of rail speeds are surveyed. It is explained that rail high speeds are feasible only for large population concentrations. The impact of high speeds on the reduction of travel times is studied. It is established a causal relationship between rail share and reduced travel times. Diversities concerning technical characteristics from one system to another are emphasized together with differences in construction costs from one case to another.