A method for monitoring the evolution of stray currents of a railway infrastructure , the railway infrastructure comprising: - rails laid on a ground and insulated from the ground by an insulation system , the rails defining at least one track section (S, S'); - substations generating a voltage, preferably DC, to supply a rail vehicle; and - a monitoring system comprising at least one ground-rail voltage sensor and at least one calculation unit ; characterised in that the railway infrastructure further comprises at least one stabilised current source , in that the monitoring method comprises an operating phase (P2) comprising at least the following steps: - (P210) emission of a stabilised current by each current source in at least one of the rails; - (P230) measurement of the voltage (T2) generated by the stabilised current between the rails and the ground by the at least one rail-ground voltage sensor ; - (P260) calculation, by the calculation unit , of the current (C2, C'2) flowing in each section (S, S') from the current source; and - (P270) analysis by the calculation unit of the voltage measured by the rail-ground voltage sensor and of the calculated current and detection of a possible degradation of the insulation between the rails and the ground , and in that , during the analysis phase (P270), the calculation unit analyses the voltage measured by the ground-rail voltage sensor and the calculated current and detects a possible degradation of the insulation between the rails and the ground by comparing the measured voltage with a previous value of ground-rail voltage (T1, T2) on the one hand, and the calculated current with a previous value of the current (C1, C'1, C2, C'2) flowing in the rails on the other hand. - rails laid on a ground and insulated from the ground by an insulation system , the rails defining at least one track section (S, S'); - substations generating a voltage, preferably DC, to supply a rail vehicle; and - a monitoring system comprising at least one ground-rail voltage sensor and at least one calculation unit ; characterised in that the railway infrastructure further comprises at least one stabilised current source , in that the monitoring method comprises an operating phase (P2) comprising at least the following steps: - (P210) emission of a stabilised current by each current source in at least one of the rails; - (P230) measurement of the voltage (T2) generated by the stabilised current between the rails and the ground by the at least one rail-ground voltage sensor ; - (P260) calculation, by the calculation unit , of the current (C2, C'2) flowing in each section (S, S') from the current source; and - (P270) analysis by the calculation unit of the voltage measured by the rail-ground voltage sensor and of the calculated current and detection of a possible degradation of the insulation between the rails and the ground , - (P210) emission of a stabilised current by each current source in at least one of the rails; - (P230) measurement of the voltage (T2) generated by the stabilised current between the rails and the ground by the at least one rail-ground voltage sensor ; - (P260) calculation, by the calculation unit , of the current (C2, C'2) flowing in each section (S, S') from the current source; and - (P270) analysis by the calculation unit of the voltage measured by the rail-ground voltage sensor and of the calculated current and detection of a possible degradation of the insulation between the rails and the ground , and in that , during the analysis phase (P270), the calculation unit analyses the voltage measured by the ground-rail voltage sensor and the calculated current and detects a possible degradation of the insulation between the rails and the ground by comparing the measured voltage with a previous value of ground-rail voltage (T1, T2) on the one hand, and the calculated current with a previous value of the current (C1, C'1, C2, C'2) flowing in the rails on the other hand. <EOS>