Included are: an information management system that manages monitoring-target condition information output from condition-monitoring target devices; cameras that are incorporated in respective train cars and take images of the condition-monitoring target devices; a transmission device that is connected to an in-train transmission channel and transmits imaging data from the camera; a camera-control central device that is connected to the information management system and the transmission device, monitors the monitoring-target condition information sent from the information management system, determines whether the condition-monitoring target devices are in a normal condition, and generates a frame-rate control signal for adjusting a frame rate of imaging data; and a camera-control terminal device that is connected to the transmission device and the camera and adjusts the frame rate of imaging data sent from the camera based on the frame-rate control signal.