A train monitoring and reporting system in which each car of a multi-car train is provided with sensors to monitor brake, door, motor and other functions. A controller in each car sequentially and repetitively reviews the condition of each sensed function and evaluates the conditions to determine whether a fault condition exists. The evaluation result is stored and the review is continued and repeated. The lead car of the train repetitively and sequentially interrogates the storage units in each car for each type of fault condition, stores the responses to the interrogation and displays to the motorman any faults reported. The cars communicate through a multiplex data link system which connects the cars in series in a multiplex current loop. The number of times each fault occurs is counted, the count being then available for readout by maintenance personnel.