KarTrak labels were one of the many answers to the question of how to track railcars. The AAR passed a rule that by 1967, all equipment was to wear the barcode labels in an attempt to keep track of freight cars by computer. The system never really worked well and the system only had about an 80% successful read rate. By 1977, the KarTrak system was abandoned in favor of RFID (Radio Frequency ID) which is still in use today.