A train forewarning braking system is disposed between a train (40) and a track (50), is electrically connected to a traffic control center (60), and has an image monitoring module (10). The image monitoring module (10) is disposed around the track (50), is electrically connected to a control system (41) and the traffic control center (60), and has multiple image capture units (11) and multiple display units (12). The image capture units (11) are disposed at spaced intervals near the track (50) and are electrically connected to the control system (41) to capture images of the environment around the track (50). The display units (12) are disposed on the train (40) and the traffic control center (60), and are electrically connected to the control system (41) to display the images captured by each one of the image capture units (11).