A train information management apparatus comprising: a first information transmitting unit connected to a first trunk transmission line disposed across a plurality of cars, which configure a formation of a train, and a second trunk transmission line disposed across said plurality of cars, which configure the formation of the train, and forming a redundant system of the first trunk transmission line, the first information transmitting unit including a first train-control-information generating unit configured to generate, based on control input information including notch information, first train control information serving as a control command signal for a receiving device mounted on the car and a first packet generating unit configured to increment a sequence number by 1, every time the first train control information is generated, and generate a first packet in which the sequence number has been given to the first train control information and alternately transmit, in a predetermined period, the first packet to the first trunk transmission line and the second trunk transmission line; and a second information transmitting unit connected to the first trunk transmission line and the second trunk transmission line, the second information transmitting unit including a second train-control-information generating unit configured to generate second train control information, which is train control information same as or different from the first train control information, and a second packet generating unit configured to increment a sequence number by 1, every time the second train control information is generated, and generates a second packet in which the sequence number same as the sequence number given to the first packet has been given to the second train control information and transmit, in the every predetermined period, the second packet to a trunk transmission line on the opposite side of the trunk transmission line to which the first packet was transmitted, characterised in that the second train control information unit is generating said second train control information based on the control input information starting from the time at which the time obtained by multiplying the predetermined period with 1/2 has elapsed from a time point at which the first train control information was transmitted. a first information transmitting unit connected to a first trunk transmission line disposed across a plurality of cars, which configure a formation of a train, and a second trunk transmission line disposed across said plurality of cars, which configure the formation of the train, and forming a redundant system of the first trunk transmission line, the first information transmitting unit including a first train-control-information generating unit configured to generate, based on control input information including notch information, first train control information serving as a control command signal for a receiving device mounted on the car and a first packet generating unit configured to increment a sequence number by 1, every time the first train control information is generated, and generate a first packet in which the sequence number has been given to the first train control information and alternately transmit, in a predetermined period, the first packet to the first trunk transmission line and the second trunk transmission line; and a second information transmitting unit connected to the first trunk transmission line and the second trunk transmission line, the second information transmitting unit including a second train-control-information generating unit configured to generate second train control information, which is train control information same as or different from the first train control information, and a second packet generating unit configured to increment a sequence number by 1, every time the second train control information is generated, and generates a second packet in which the sequence number same as the sequence number given to the first packet has been given to the second train control information and transmit, in the every predetermined period, the second packet to a trunk transmission line on the opposite side of the trunk transmission line to which the first packet was transmitted, characterised in that the second train control information unit is generating said second train control information based on the control input information starting from the time at which the time obtained by multiplying the predetermined period with 1/2 has elapsed from a time point at which the first train control information was transmitted.