A Pressurized Tank Car Inspection System for Railroad Transportation Security

Pressurized rail tank cars transport large volumes of volatile liquids and gases throughout the country, much of which is hazardous and/or flammable. Our group is developing a trackside inspection system for these tank cars. It consists of five narrow frequency band pressure sensors with center frequencies of 40 and 75 kHz, a broad band microphone for sound normalization and three video cameras. In addition, a 5 cm times 5 cm NaI(Tl) radiation detector provides radiological data on the passing trains every 60 seconds. During operation, an audio frequency spectrum is associated with each frame of the video camera as the train passes by the system at normal speeds, and the spectra are inspected for high frequency sounds associated with leaks. A 10 m tall tower houses the system positioned approximately 10 m from the center of a rail line and siding located in Bowling Green, KY (USA). The system is controlled by a website and server located at the tower and the Internet connection utilizes WiFi (802.11 g) radios.