A system for monitoring railroad cars comprising a hatch cover assembly including a cover body, a sensor, a wireless transmitter for transmitting data received from the sensor, a wireless receiver for receiving the data from the wireless transmitter, and a satellite transmitter for transmitting the data to a satellite. The wireless receiver and the satellite transmitter are attached to the hatch cover assembly. In one embodiment, the sensor is a pressure sensor having a sensing unit situated in the plenum of a vented hatch cover. In another embodiment, the sensor is an air flow sensor having a sensing unit situated in the plenum of a vented hatch cover. In another embodiment, the sensor is a chain tension sensor attached to a handbrake chain. In another embodiment, the sensor is a hatch cover position attached to the hatch cover assembly.