A railroad vehicle monitoring system installed on a railroad vehicle includes: wireless sensor devices installed at attached equipment of the railroad vehicle, including a sensor that senses statuses of the attached equipment, configured to wirelessly transmit a sensing value sensed by the sensor in real time, and including an energy harvester configured to convert energy generated by running of the railroad vehicle into electric energy, and supply the electric energy as a power source for the sensor, a signal process in the sensing value, and wireless communication of the sensing value; sink node devices configured to wirelessly receive the sensing value and output, in real time, railroad vehicle status information obtained by integrating the received sensing value; and a vehicle status monitoring device configured to receive the railroad vehicle status information, integrate and manage the railroad vehicle status information, and output the integrated railroad vehicle status information in real time.