To meet the growing demands of further broadband communications even in the railway scenarios, millimeter (mm)-wave radio communication is a promising solution. In order to establish its system we have to consider some fundamental issues: mm-wave radio propagational properties, handovers across cells especially for high-speed railways, and spectral efficiency. We here propose a novel mm-wave train radio communication system based on our linear cell concept. To simultaneously satisfy both two different aspects "bandwidth-guaranteed" and "broadband" as a train radio system, i.e. both the passenger use and operational use, we raise five key enablers for realization of our concept. Through the discussion in this paper, we reveal the benefit and significance of the focused key enablers comprising our mm-wave linear cell concept.
