PURPOSE: To realize the transmission of picture signals in a system that can be executed by using comparatively narrow radio wave bands, and to monitor the condition of an arbitrary car at an arbitrary time in ground monitor stations, in a central monitor device of cars by pictures.

CONSTITUTION: A ground communication controller 9 calls each car 1, 2 at a fixed time interval, and controls communication in order to transmit picture signals from the upper portions of cars. When the car 1 turn comes round, for example, a call signal for specifying the car 1 is put out to a ground communication controller 5 through a ground transmitter-receiver 8, a signal transmission course 7 and a transmitter-receiver 6 on the car. Pictures at suitablde locations inside and outside cars projected by menas of a TV camera 3 are converted into picture signals by means of a pircture signal converter 4, and fed to the signal transmission course 7. Said picture signals are memorized at a storage device 11 through a picture signal converter 10 at a groung monitor station, and picture signals are fed to a monitor TV in response to the output of a select change-over device 14