The CSM on Monitoring is addressed to railway undertakings, infrastructure managers and entities in charge of maintenance (ECMs) and describes the harmonised process to be applied for the monitoring of their safety management system (for railway undertakings and infrastructure managers) and maintenance system (for ECMs) whereas the CSM on Supervision is addressed exclusively to the national safety authorities and describes the harmonised process to be set out to oversee the safety performance of the railway undertakings and infrastructure managers.