A train image monitoring system in which cameras, sensors that acquire surrounding situations, and a control device that controls the cameras and the sensors are connected by a network and mounted on a train, wherein the cameras and the sensors are mounted on a plurality of cars that form the train, characterized in that: the control device executes, based on data received by the cameras or the sensors mounted on one of the cars, control for controlling operations of the cameras or the sensors in other cars, a display device that displays data of the cameras and the sensors in association with a setting form of the cameras and the sensors in the train is connected by the network, the control device executes the control when data of one or more of the sensors exceeds a respective threshold, and the display device distinguishably displays the data of the sensors exceeding the threshold, at least one of the sensors on each car is a pantograph noise meter collecting noise that occurs around the pantograph and at least one of the cameras on each car is a pantograph camera imaging the pantograph, at least one of the sensors on each car is a truck noise meter collecting noise that occurs around the truck and at least one of the cameras on each car is a truck camera imaging a truck, at least one of the sensors on each car is an illuminometer, and the control device determines if the train enters or comes out from a tunnel based on illuminance data of the illuminometer of one of the cars by calculating an illuminance change amount and comparing the illuminance change amount with a predetermined threshold, and the control device changes first pantograph and truck noise thresholds (TH1, TH2) used outside a tunnel to second pantograph and truck noise thresholds (TH4, TH5)used inside the tunnel when the illuminance change amount falls below the predetermined threshold and switches the second noise thresholds (TH4, TH5) to the first noise thresholds (TH1, TH2) when the illuminance change amount rises above the predetermined threshold. the control device executes, based on data received by the cameras or the sensors mounted on one of the cars, control for controlling operations of the cameras or the sensors in other cars, a display device that displays data of the cameras and the sensors in association with a setting form of the cameras and the sensors in the train is connected by the network, the control device executes the control when data of one or more of the sensors exceeds a respective threshold, and the display device distinguishably displays the data of the sensors exceeding the threshold, at least one of the sensors on each car is a pantograph noise meter collecting noise that occurs around the pantograph and at least one of the cameras on each car is a pantograph camera imaging the pantograph, at least one of the sensors on each car is a truck noise meter collecting noise that occurs around the truck and at least one of the cameras on each car is a truck camera imaging a truck, at least one of the sensors on each car is an illuminometer, and the control device determines if the train enters or comes out from a tunnel based on illuminance data of the illuminometer of one of the cars by calculating an illuminance change amount and comparing the illuminance change amount with a predetermined threshold, and the control device changes first pantograph and truck noise thresholds (TH1, TH2) used outside a tunnel to second pantograph and truck noise thresholds (TH4, TH5)used inside the tunnel when the illuminance change amount falls below the predetermined threshold and switches the second noise thresholds (TH4, TH5) to the first noise thresholds (TH1, TH2) when the illuminance change amount rises above the predetermined threshold.