Nondestructive testing (NDT) is any of a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. The six most frequently used NDT methods are eddy-current, magnetic-particle, liquid penetrant, radiographic, ultrasonic, and visual testing. NDT is commonly used in forensic engineering, mechanical engineering, petroleum engineering, electrical engineering, civil engineering, systems engineering, aeronautical engineering, medicine, and art. Innovations in the field of nondestructive testing have had a profound impact on medical imaging, including on echocardiography, medical ultrasonography, and digital radiography.
Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat. Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. Numerous welding methods have been developed for the joining of semi-finished plastic materials. Based on the mechanism of heat generation at the welding interface, welding methods for thermoplastics can be classified as external and internal heating methods, as shown in Fig 1.
A speeder is a small railcar formerly used around the world by track inspectors and work crews to move quickly to and from work sites. Although slow compared to a train or car, it is called speeder because it is faster than a human-powered vehicle such as a handcar. Motorized inspection cars date back to at least 1896, when it was reported that the U.S. Daimler Motor Company created a gasoline-powered rail inspection car capable of 15 mph (24 km/h).
A defect detector is a device used on railroads to detect axle and signal problems in passing trains. The detectors are normally integrated into the tracks and often include sensors to detect several different kinds of problems that could occur. Defect detectors were one of the inventions which enabled American railroads to eliminate the caboose at the rear of the train, as well as various station agents placed along active routes to detect unsafe conditions. The use of defect detectors has since spread overseas to other railroad systems.
Eddy-current testing is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.
Predictive maintenance techniques are designed to help determine the condition of in-service equipment in order to estimate when maintenance should be performed. This approach promises cost savings over routine or time-based preventive maintenance, because tasks are performed only when warranted. Thus, it is regarded as condition-based maintenance carried out as suggested by estimations of the degradation state of an item.
Ultrasonic testing (UT) is a family of non-destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. In most common UT applications, very short ultrasonic pulse waves with centre frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz, are transmitted into materials to detect internal flaws or to characterize materials. A common example is ultrasonic thickness measurement, which tests the thickness of the test object, for example, to monitor pipework corrosion and erosion. Ultrasonic testing is extensively used to detect flaws in welds.
The Viewliner is a single-level railroad car type operated by Amtrak on most long-distance routes operating east of Chicago. The first production cars, consisting of an order of 50 sleeping cars, entered service in 1994. From 2015-2016, 70 Viewliner II baggage cars entered service. The new baggage cars are used on all Amtrak trains with full baggage cars, both single-level and bi-level, and replaced all of the Heritage Fleet baggage cars that Amtrak inherited from the freight railroads when it was established in 1971. From 2016-2019, 25 Viewliner II dining cars entered service, which replaced all of the Heritage Fleet dining cars. In 2019, 10 Viewliner II baggage-dormitory cars entered service. The last cars to enter service were 25 Viewliner II sleeping cars in 2021.
An axle counter is a system used in railway signalling to detect the clear or occupied status of a section of track between two points. The system generally consists of a wheel sensor and an evaluation unit for counting the axles of the train both into and out of the section. They are often used to replace a track circuit.
A track geometry car is an automated track inspection vehicle on a rail transport system used to test several parameters of the track geometry without obstructing normal railroad operations. Some of the parameters generally measured include position, curvature, alignment of the track, smoothness, and the crosslevel of the two rails. The cars use a variety of sensors, measuring systems, and data management systems to create a profile of the track being inspected.
Phased array ultrasonics (PA) is an advanced method of ultrasonic testing that has applications in medical imaging and industrial nondestructive testing. Common applications are to noninvasively examine the heart or to find flaws in manufactured materials such as welds. Single-element probes, known technically as monolithic probes, emit a beam in a fixed direction. To test or interrogate a large volume of material, a conventional probe must be physically scanned to sweep the beam through the area of interest. In contrast, the beam from a phased array probe can be focused and swept electronically without moving the probe. The beam is controllable because a phased array probe is made up of multiple small elements, each of which can be pulsed individually at a computer-calculated timing. The term phased refers to the timing, and the term array refers to the multiple elements. Phased array ultrasonic testing is based on principles of wave physics, which also have applications in fields such as optics and electromagnetic antennae.
Rail inspection is the practice of examining rail tracks for flaws that could lead to catastrophic failures. According to the United States Federal Railroad Administration Office of Safety Analysis, track defects are the second leading cause of accidents on railways in the United States. The leading cause of railway accidents is attributed to human error. The contribution of poor management decisions to rail accidents caused by infrequent or inadequate rail inspection is significant but not reported by the FRA, only the NTSB. Every year, North American railroads spend millions of dollars to inspect the rails for internal and external flaws. Nondestructive testing (NDT) methods are used as preventive measures against track failures and possible derailment.
A work train is one or more rail cars intended for internal non-revenue use by the railroad's operator. Work trains serve functions such as track maintenance, maintenance of way, revenue collection, system cleanup and waste removal, heavy duty hauling, and crew member transport.
Thermographic inspection refers to the nondestructive testing (NDT) of parts, materials or systems through the imaging of the temperature fields, gradients and/or patterns ("thermograms") at the object's surface. It is distinguished from medical thermography by the subjects being examined: thermographic inspection generally examines inanimate objects, while medical thermography generally examines living organisms. Generally, thermographic inspection is performed using an infrared sensor.
Loram Maintenance of Way, Inc. is a railroad maintenance equipment and services provider. Loram provides track maintenance services to freight, passenger, and transit railroads worldwide, as well as sells and leases equipment which performs these functions.
A train inspection system is one of various systems of inspection which are essential to maintain the safe running of rail transport.
Floyd Alburn Firestone (1898–1986) was an acoustical physicist, who in 1940 while a professor at the University of Michigan invented the first practical ultrasonic testing method and apparatus. He was granted U.S. patent 2,280,226 for the invention in 1942. Manufactured by Sperry Corporation, the testing device was known variously as the Firestone-Sperry Reflectoscope, the Sperry Ultrasonic Reflectoscope, the Sperry Reflectoscope and sometimes also just as a Supersonic Reflectoscope, the name Firestone had coined for the instrument. The technology is not just used in quality control in factories to reject defective parts before shipment, but also revolutionized transportation safety. For example, ultrasonic testing is used for safety maintenance inspection of railroad cars, particularly axles and wheels, aircraft, particularly fuselages, and other transportation vessels for material fatigue. Dr. Firestone's ultrasonic pulse echo technique for metal defect testing was also later applied in medical diagnosis, giving birth to the field of Echocardiography and to the field of Medical Ultrasonography, generally. Dr. Firestone was the editor of the Journal of the Acoustical Society of America from 1939 to 1957. Among Firestone's many other inventions, were in a single year an “automatic device for the minute inspection of flaws”, “a new and useful improvement in hook-up of electrical apparatus”, and “[a] device for measuring noise”, and, even, later a “musical typewriter”.
Welding of advanced thermoplastic composites is a beneficial method of joining these materials compared to mechanical fastening and adhesive bonding. Mechanical fastening requires intense labor, and creates stress concentrations, while adhesive bonding requires extensive surface preparation, and long curing cycles. Welding these materials is a cost-effective method of joining concerning preparation and execution, and these materials retain their properties upon cooling, so no post processing is necessary. These materials are widely used in the aerospace industry to reduce weight of a part while keeping strength.
The 2018 Station Square Derailment happened in Pittsburgh, Pennsylvania, United States, on the afternoon of August 5, 2018. The equipment involved was a Norfolk Southern manifest freight train, about 57 cars long and was traveling at approximately 25 MPH at the time of the incident. 10 cars derailed, 3 fell onto the Port Authority of Allegheny County tracks, blocking the line and taking 6 containers with them, while the other 7 and their associated containers remained on the NS right of way. Nobody was injured, and the other 47 cars were not damaged. The accident caused $1.8M in damage, and was caught on video.
