A monitoring method and system monitor a transmitted current that is injected into conductive components of a route traveled by vehicle systems, monitor a received current that represents a portion of the transmitted current that is conducted through the conductive components of the route, examine changes in the transmitted and/or received current over time to determine when the vehicle systems are on the route between a first location where the transmitted current is injected into the conductive components and a second location where the received current is monitored, and examine the changes in the transmitted and/or received currents. The changes are examined to identify (a) a contaminated portion of a surface on which the route is disposed, (b) a foreign object other than the vehicle systems that is contacting the route, and/or (c) a damaged or broken portion of at least one of the conductive components of the route.