Sunday, April 20, 2014

Essential Information About Rail Track Inspection

By Essie Osborn


Railroads are an important form of transport. With many railroads being old and heavily used, inspecting them is essential to ensure safety. Rail track inspection is the process of examining railroads for flaws that may cause catastrophic accidents. Many effects influence railroad defects. They include thermal stresses, shear stresses, wheel or rail contact stresses, dynamic effects and residual stresses.

The flaws that contact stresses or rolling contact failure cause include squats, tongue lipping and gauge corner cracking. The other types of external and internal flaws that can occur on railroads include wheel burn, transverse fissures, shelling, seams, corrosion and inclusions. Water and other kinds of liquids can cause railroads to crack.

Defects can be found on various parts of a railroad including the web, head, switchblades, foot, bolt holes and welds. Most flaws occur in the head but the entire rail has to be inspected. Many different methods are used to detect defects in rails. The most popular method is ultrasound. The other methods used are radiography, magnetic flux leakage, magnetic particle inspection, electromagnetic acoustic transducer and eddy current inspection.

Engineers use inspection techniques in different ways. They may use probes and transducers in a handheld setup or a hand pushed trolley. They use probes and transducers when inspecting a precise location or a small section of the rail. They often use these devices to follow up on areas that rail inspection cars have been used to inspect.

Handheld devices are useful for inspecting railway tracks that are used heavily since it is relatively easy to remove them. Nonetheless, using these devices is considered to be tedious and slow when thousands of miles of track need to be inspected. Rail inspection cars are more convenient to use when thousands of miles of railroad have to be inspected.

Railroad inspection cars use several non destructive testing techniques. Induction and ultrasound testing methods can be used in cars, which operate at speeds exceeding 30 miles per hour. These vehicles are equipped with high speed computers, which utilize advanced programs to recognize patterns. They also have storage space, tool cabinets, and workbenches.

Specialized laser scanners are also used to perform railroad inspections. They are usually used to measure the rail gauge. After railroad inspections identify potential problems, work crews are hired to rectify the problems. All trains that are using that particular stretch of railway are notified that repair crews are in the area. Special warning and speed limits are issued to train crews.

In most cases, trains that are scheduled to use a particular stretch of railroad are requested to use alternate routes. If the repairs that need to be performed are extensive such as tie replacement, crossing repairs or switch repairs, train traffic can be halted until the repairs are complete. If a derailment has taken place, the recent track inspections are examined to determine if a pre existing defect may have contributed to the accident. In some cases, repeated problems may occur on a certain stretch of rail track. In such a case, special inspections are carried out to examine the problem and seek to resolve it.




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