ULTRASONIC TESTING OF RAILS BY SPURT CAR
Introduction
12.1.1 Continuous testing of rails by manual flaw detectors is strenuous and demands continuous concentration on CRT screen, also the speed achievable is only 2/6 track km in a day. An equipment which can shortlist likely defective spots quickly can improve the effectiveness of the testing.
12.1.2 Self Propelled Ultrasonic Rail Testing (SPURT) Car has been procured for this purpose and is in operation since May’88 over Indian Railways. This car tests both the rails while traveling up to 30 km/h. Most of the testing operations have been automated in this car.
12.2 Description of SPURT Car
12.2.1 SPURT Car has water supply system with a capacity of 4000 litres guiding system for probe beam positioning and air system for lifting and lowering of probe. Probes used are of the following types:
| Probes | Defect type |
| 0o (Normal) | Horizontal flaws |
| 70o Central | Vertical transverse flaw |
| (forward and backward) | |
| 70o side wise | Vertical transverse flaw |
| 35o (forward and backward) | Star cracks |
| 550 | Vertical longitudinal flaws. |
12.2.2 As SPURT car tests at higher speed, observation for flaws can not be done manually. Identification of defect is done electronically according to laid down logics. Also it has computer for tabulating, printing and storage of data.
12.2.3 Comparative characteristics of manual USFD tester and SPURT car are tabulated below:
| SPURT car | USFD manual machine |
| Real time recording of defects | No automatic recording of defect. |
| Analysed by computer hence less strenuous Concentration.Testing is objective | Testing requires sustained and intense Testing depends on the interpretation by operator |
| Testing of 80-120 track km per day. | Testing of 2 to 6 track km per day. |
| Testing of 2 to 6 track km per day.and severity classification is dependent on visual information. So classification is not possible | Ultrasonic information is supplemented by visual information also. So severity classification is done |
| Repetition of test at a spot is difficult due speed and path constraint | Repetition of test at a spot can be conveniently to done |
To take advantage of both machines, the method used by Railways having SPURT car is to use both as complementary to each other. SPURT car short lists the likely defective spots and manual equipment is used to check only these locations. During this check the severity classification is done.
12.3 Locations not tested by SPURT Car
12.3.1 Fishplated joint causes damage to SPURT car probes and also efficacy of testing reduces depending upon condition of joints, therefore only LWR/CWR lengths are normally tested by SPURT car. Also probes are lifted on points and crossings, SEJ’s and buffer rails and these remain untested. At locations fitted with ground rail lubricators, probes are also lifted and hence testing is not done at such locations.
12.3.2 Testing of rail with surface defects like wheel burn and scab is also to be done manually.
12.3.3 The real time out put as well as final defect report contains the information about stretches not tested by SPURT car.
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