System for determining an adhesion value between wheel and rail for a railway vehicle, comprising: - an optical information acquisition means arranged to acquire optical information from the rail; - a database arranged, at least in a learning phase, to store the acquired optical information and associate the acquired optical information with a respective real wheel-rail adhesion value substantially measured at the time of acquisition of the optical information by the optical information acquisition means; - a control unit arranged to determine the current wheel-rail adhesion value on the basis of a comparison between current acquired optical information and the optical information previously stored in the database; wherein the control unit is arranged to determine that the current wheel-rail adhesion value associated with the current optical information acquired by the optical information acquisition means corresponds to the adhesion value associated with the optical information stored in the database having the highest degree of similarity with the current acquired optical information; and being characterized in that the control unit is configured to determine which is the optical information stored in the database having the highest degree of similarity with the current optical information through image recognition algorithms based on artificial intelligence and/or machine learning. - an optical information acquisition means arranged to acquire optical information from the rail; - a database arranged, at least in a learning phase, to store the acquired optical information and associate the acquired optical information with a respective real wheel-rail adhesion value substantially measured at the time of acquisition of the optical information by the optical information acquisition means; - a control unit arranged to determine the current wheel-rail adhesion value on the basis of a comparison between current acquired optical information and the optical information previously stored in the database; wherein the control unit is arranged to determine that the current wheel-rail adhesion value associated with the current optical information acquired by the optical information acquisition means corresponds to the adhesion value associated with the optical information stored in the database having the highest degree of similarity with the current acquired optical information; and being characterized in that the control unit is configured to determine which is the optical information stored in the database having the highest degree of similarity with the current optical information through image recognition algorithms based on artificial intelligence and/or machine learning. wherein the control unit is arranged to determine that the current wheel-rail adhesion value associated with the current optical information acquired by the optical information acquisition means corresponds to the adhesion value associated with the optical information stored in the database having the highest degree of similarity with the current acquired optical information; and being characterized in that the control unit is configured to determine which is the optical information stored in the database having the highest degree of similarity with the current optical information through image recognition algorithms based on artificial intelligence and/or machine learning.