Ultrasonic Rail Flaw Testing Car
As the portable ultrasonic rail flaw detector can test only 2-3 km of rails everyday, advanced railways such as German Railways have developed a rail testing car that can test a much longer length of track much more effectively. The test car tests the track at a speed of 30 kmph and each of the two rails is tested ultrasonically by means of five probes (0 o , ±35 o , ±70 o ) and an airborne sound assembly. The test results are recorded photographically on a tape, a subsequent examination of which can reveal all the flaws. The flaws can then be properly classified. Their position in the track can also be pinpointed with respect to kilometrage to an accuracy of 1 m. This special car tests the track during the day and covers 100-200 km per day. The car covers approximately 20,000 km of track every year on German Railways. The average cost of testing is Rs 300-500 per km of the track. With the present trend in increase in speed, the need for ultrasonic inspection of rails is felt all the more to avoid hazards due to rail fractures, and in this context, the use of the test car on Indian Railways is considered a technical and operational necessity.