Passive replication methods and systems to facilitate fault tolerance in a network routing system are provided. In one embodiment, a fault associated with a processing engine (PE) of a network routing system is detected by monitoring the health of the network routing system PEs. Responsive to detecting a fault (e.g., a link failure, a failure of a virtual router (VR) or a failure of the PE): VRs that were operating on the PE prior to detection of the fault are identified; configuration information (e.g., a set of command lines in a configuration file) associated with the identified VRs is identified; and the identified VRs are dynamically recreated on a new PE based on the configuration information. For example, a command line interface engine may replay the command line set with a new slot ID and a PE ID of the new PE to recreate the VRs on the new PE.