In this paper, we propose a Benders' decomposition algorithm to tackle the real time railway traffic management problem. We decompose the mixed-integer linear programming formulation at the basis of RECIFE-MILP, a state-of-the art algorithm for the real time railway traffic management problem. In our Benders' decomposition algorithm, train routing and scheduling decisions are made in the master problem. Given these decisions, we compute the trains arrival and passing times in the slave problem to deduce the total delay. By applying our Benders' decomposition algorithm to RECIFE-MILP, we tackle large instances representing traffic in the Rouen-Rive-Droite control area.