Section 11(4) in The Calcutta Metro Railway General Rules, 2000
(4)In the event of the driving apparatus in the leading cab becoming defective, the motorman may change the cab from front to rear and take the train back to the previous station operating the rear cabin driving apparatus with the permission of the Traffic Controller who will give such permission after duly verifying the clearance of the line upto the station in rear where the train is to be received. In case the train has to be taken to a station in advance, another motorman will be arranged.
