Although Okumura-Hata prediction model has been a widely used model to estimate radio network coverage, its application in railways environment requires validation and additional studies. This paper presents the main results on a study based on measurements campaigns, and identifies significant differences in parameters that characterize the radio propagation in railways environment, for the 900 MHz band. Both the propagation slope and standard deviation measured values are presented in this work. For validation, the developed model setup was used in the radio planning process, setting a live GSM-R pilot network, operating in Portugal.