Abstract: In a railway information transmission method and system wherein information is transmitted by a consecutive transmission mode between on-vehicle control equipment and ground control equipment, a redundant code which is updated in accordance with a predetermined procedure every transmission processing is affixed to information to-be-communicated, the information being then transmitted, and on a reception side, the redundant code which is contained in the received information is correlated with a redundant code which is created on this side and which is updated in a predetermined procedure. Thus, the trouble of a transmission path can be simply found, and further, the safety of train service based on an automatic train control or the like can be enhanced.

Abstract: A train detection system is capable of realizing reliable train detection with a train detection apparatus of simple construction using a track circuit. This is attained by a transmitter 11a adding data of a first unique code to a train detecting signal received from wayside controller 100 and transmitting it to a track circuit; a receiver 11b adding data of a second unique code to the train detecting signal added with the first unique code data received from the track circuit and transmitting it to the wayside controller 100; and the wayside controller 100 checking whether or not the data received from the receiver 11b agrees with predetermined data.

Abstract: A power switching circuit is provided, which automatically performs the necessary power switching, and by which the power specifications of external devices in a network can be uniformly determined. The power switching circuit comprises, for each external device, (i) a first diode for transmitting the power from the main device to the network, and for preventing power from reversely flowing from the network to the main device; (ii) a second diode for transmitting power from the external device to the main device, and for preventing power from reversely flowing from the main device to the external device; and (iii) a port for physically connecting the main device and the external device. The connection between the external devices is maintained regardless of the state of the power of the main device.