Smart Railway Operation Aid System for Facilities With Low-Safety Requirements. - Antonio Torralba 002; María García-Castellano; Miguel Hernández-González; Juan Pablo García-Martín; Ventura Pérez-Mira; Roberto Fernandez-Sanzo; Antonio Jacome-Moreno; Francisco Javier Gutierrez-Rumbao (IEEE Intell. Transp. Syst. Mag., 2021)