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For four types of railway rails, corresponding rolling tests have been executed by using the JD-1 wheel/rail simulation device based on the Hertz simulation method, which can ensure the reciprocal contact condition between simulation rail and wheel under experimental conditions approximate to practical contact conditions. The results indicate that, for the rail material which has a higher hardness, the wear volume was less and the plastic deformation layer was thinner after the rolling test, but the crack propagation was more significant and the fatigue damage was severer, showing that its wear resistance was better. The analysis shows that the fatigue resistance of U71Mn rail was better, and considering fatigue is the main failure type for high-speed rail, so it is more suited to the high-speed railway. [ABSTRACT FROM AUTHOR]

Derailments of trains often occur due to the wheel-rail contact failure caused by the impact of the trains with road vehicles at road-rail crossings. Frontal collisions of passenger trains onto stuck road vehicles occur frequently at such road-rail crossings even where active warning systems are installed. Such collisions are often fatal and cause significant damages to vehicles and the infrastructure especially when they incur derailments. Innovations in passive railway infrastructure designs for mitigating the severity of collision induced derailments are rare. This paper presents a formulation for a passive road-rail crossing involving stiffened edges of the raised road pavement to minimise the risk of failure of wheel–rail contact using a nonlinear three-dimensional multibody dynamics model. Severe derailment scenarios of trains passing through the passive and normal road-rail crossings have been analysed and presented. The innovative design of the road-rail crossing with passive track structure presented in the paper is shown to reduce the failure of the wheel-rail contact and hence the train-truck frontal collision derailment potential. [ABSTRACT FROM AUTHOR]

The interaction between wheel and rail is still a great problem of railway engineering. A mathematical model of the system Vehicle-Track, previously developed by the same authors and a newly developed model of vehicle wheel that is scaled, are used to create a new mathematical model. This model allows to determine changes of dynamical characteristics in rails and to evaluate physical and mechanical properties of the system Vehicle-Track. Results, obtained when rail is in contact with vehicle scaled wheel are compared with results obtained when the wheel is without scales. [ABSTRACT FROM AUTHOR]

The effect of microstructure on the spalling damage in a heavy-haul 20Mn2SiCrMo bainitic wing rail was investigated. The results show that spalling damage is strongly correlated to the detailed microstructure factors which contribute to the crack propagation resistance at different levels. It is demonstrated that comparing with blocky martensite/austenite (M/A) constituents, film-like M/A constituents have better performance to retard crack propagation. Moreover, the type and proportion of M/A constituents are affected by the isothermal holding temperature during heat treatment, where typical blocky M/A constituents are found in the temperature range from 360 °C to 400 °C. [ABSTRACT FROM AUTHOR]

A three-dimensional ballastless track model was established using a finite element method to simulate the rail condition before and after rail break. The distribution of the rail longitudinal stress was analyzed under certain thermal stress. In addition, experiments were also conducted in order to validate the simulation results using rail longitudinal stress test equipment. It was found that the simulation results agreed reasonably well with the experimental results. The tests show that the simulation results could correctly predict the longitudinal stress distribution in the rail. Finally, rail longitudinal stress distributions under different thermal stress were calculated using this model; this is helpful for future application to determine when and where there may be a rail break. [ABSTRACT FROM AUTHOR]

The investigations of defects of structure of rail joints, made by flash-butt welding, were carried out. The defects were detected at the fracture surface of joints during static bending tests and also after fracture under the operation conditions. The analysis of microstructure and chemical heterogeneity of the fracture surface was performed using Auger-microprobe JAMP 9500F of the JEOL company (Japan). The defects formed as a result of deviation from the standard welding conditions include lacks of penetration and inclusions of iron-manganese silicates which considerably decrease the values at mechanical tests of welded joints. Their presence in the welded joints is not admissible. Clusters of inclusions of aluminium silicates, the so-called dead spots, and oxide films of the more complicated composition are formed in the joint on the basis of non-uniformly distributed non-metallic inclusions of rail metal. The dead spots of small area do not influence the values at mechanical tests of welded joints. Their total area on the fracture should not exceed 15 mm2. On the basis of carried out investigations the criteria of quality evaluation of the high-strength steel joints, made by flash-butt welding using modern control systems, were determined. [ABSTRACT FROM AUTHOR]

Squat flaws, when left unsupervised, can pose a threat to the safety of railway traffic. Unfortunately, as surface flaws, they cannot be detected by traditional ultrasonic methods. The application of eddy current to their detection is extremely difficult in the conditions occurring on the railway track. It seems that vision-based techniques can be a good alternative solution. The paper presents an algorithm allowing for the detection of these flaws. It uses wavelet transform to extract the rail from the background of the image. A Gabor filter bank along with a support vector machine (SVM) as a classifier were used in the squat detection process. The optimal number of features used to discriminate between the squat and the area without squat was selected with the help of the sequential feature selection method. The overall classification rate for the system was 93%. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the initiation and propagation behaviour of squat-type cracks in rail steel using mechanical and metallurgical analysis simultaneously. Rails with squat defects were removed from the site and inspected visually, ultrasonically, optically and by using electron microscopy. The contact stresses on a rail from a wheel are critically evaluated and rolling contact fatigue crack direction, initiation and propagation have been evaluated using stress theory and validated with metallurgical observations. The hardness of the rail surface was much higher than that of the adjacent rail matrix and this was comparable with that of a white etching layer. Squats were observed near the white etching layer. The squats formed an angle of 20–30° with the horizontal surface. Ultrasonic testing predicted the actual shape of the squat under the surface. Scanning electron microscopic observation revealed differences in the rolling contact behaviour between the direction of train travel and the opposite direction. Based on metallurgical research, a mechanism for squat initiation and propagation has been proposed in this paper. [Copyright &y& Elsevier]

Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (ΔKeq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (ΔKeq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the ΔKeq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the ΔKeq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state. [ABSTRACT FROM AUTHOR]

With increased axle weight and faster trains, the need for routine inspection of rails becomes much more important. The approaches currently being used in the rail industry are either inspection trains, dual-purpose road/track vehicles or hand-held trolleys using ultrasonic, eddy current, alternating current field measurement (ACFM) or magnetic flux leakage sensors. The vehicle-mounted systems generally provide information on defect locations but less robust data about defect sizes, which can be provided by hand-held systems. In this research, a robotic system has been proposed for the detection and characterisation of rolling contact fatigue (RCF) cracks on in-service rail tracks, which is designed to locate and then systematically scan the defects to provide more detailed data on the cracks. The system consists of a mechanised trolley, an FS02N Kawasaki robot arm and a commercially available AMIGO ACFM system, supplied by TSC Inspection Systems. This paper outlines the experimental results when the trolley is stationary and the robot arm is used to survey the rail head. It has been shown that the proposed system has the potential to improve the quality of RCF crack characterisation and could be used to autonomously inspect the rail tracks. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a recently proposed mechanics-based model for the wear coefficient of rail steels is experimentally validated and implemented to obtain useful predictive wear models for some popular railway steels. The model is then implemented to investigate the feasibility of top of rail (TOR) friction modifiers (FMs) for wear-type rail corrugation control. The experimental results confirm the analytical prediction of the first transition (step change in value) of the wear coefficient based on known conditions of creep and load. The implementation of the model under dry and friction-modified conditions shows a substantial reduction in the wear coefficient from 1.6×10−09 kg/Nm to 0.34×10−09 kg/Nm, respectively. This along with an approximate 50% reduction in friction coefficient, is predicted to result in substantial decreases in corrugation growth rate and grinding costs of ∼20 times under the experimentally measured conditions of friction modifiers. [Copyright &y& Elsevier]

Abstract: Main results of comprehensive research of rolling contact defects initiation are presented in this contribution. Description of own experimental study has been preceded by practical experience of a wheelset producer. A line rolling/sliding contact case with creepage of 0.75% was investigated using a unique test machine. The rail disc was made from Class C steel grade while the wheel disc from R7T steel grade. Unlike the standard twin-disc test, the diameter of the rail disc was 2.6 times bigger than the diameter of the wheel disc. Development of contact cracks and accumulation of shear strain for the wheel material R7T during rolling contact loading were namely evaluated. On the basis of test conditions, simulation by FEM was performed. As the result, very good prediction of shear strain accumulation was achieved using the AbdelKarim–Ohno cyclic plasticity model. The proposed computational strategy can be used for fatigue life prediction till initiation of a crack caused by low-cycle fatigue or by ratcheting failure. [Copyright &y& Elsevier]

Corrosion of rails has been a cause of concern for the Southern Railways. Out of many causes, corrosion due to toilet droppings is more pronounced. In this study, the role of bacteria, viz. heterotrophic bacteria, manganese oxidizers, iron bacteria and ureolytic bacteria on rails have been studied. The attachment of rod- and cocci-shaped bacteria were noticed on the corroded rail sample. A porous rust layer and fine cracks were noticed on the steels. Twenty bacterial strains were identified by molecular technique and most of the bacteria were positive in citrate and urease test, where 85% species could tolerate high pH 9.0. X-ray photoelectron spectroscopy revealed that FeOOH in the bare steel was converted to ferric oxides and hydroxides due to bacterial corrosion. When the rail sample was tested at low AC perturbations, the biofilm provided protection to the rails. However, at higher anodic potentials, the biofilm was not able to protect the bare material. It could be assumed that the ureolytic bacteria and iron/manganese oxidizers may create differential pH gradient on the metal surface which enhances the electrochemical reaction of the metal surface. [ABSTRACT FROM AUTHOR]

The article focuses on the use of eddy current test method to detect early the development of fine crack pattern in rails known as rolling contact fatigue (RCF). It says that the rail inspection method is based on induction of electromagnetic that makes it to work without contact. It states that the technique, which is used on grinding trains, eddy current trolleys, and inspection trains in many European countries, is suitable for high speed tests required on test trains.

Rolling Contact Fatigue (RCF) is a major cause of rail failure leading to replacement of rails. RCF defects are caused by a combination of high normal and tangential stresses between the wheel and rail. In this study, a methodology has been proposed to evaluate P-F (Potential failure-functional failure) interval of RCF defects based on RCF defect rate distribution and fatigue design life distribution. For estimating fatigue design life distribution, load under variable amplitude has been considered which is a case in the mixed traffic scenario. Stochastic S-N curve has been considered to account for probabilistic nature of fatigue life. The stress history can be calculated from the actual load history. RCF defect distribution can be estimated from the probability density function of the defects from the actual field data. The proper estimation of P-F interval will help the infrastructure managers to define rail inspection interval scientifically. [ABSTRACT FROM AUTHOR]

Abstract: In the past ten years ultrasonic guided wave systems have become widely used for the rapid large-scale examination of pipes and pipelines in pressure containing systems, for the detection of corrosion and other degradation in service. As a result, the characteristics of the guided wave modes existing in pipes have been studied extensively and are well understood. Advantage is taken of the fact that a pipe is essentially a one-dimensional object and that guided waves travelling along it will return to the sensor location for detection. Guided waves may also be applied to other components which are non-cylindrical, either those of constant cross-section such as railway rails or structural I beams, or constructions consisting of plates. However, in both cases the guided wave systems are more complex than in simple cylinders and successful application of this technique for large scale examination of these constructions requires further development of the understanding of the properties of the waves propagating and regularities of their generation. This paper describes work carried out under the EU-funded LRUCM project to develop techniques for detection of corrosion and cracking in railway rails and structural sheet piles used to retain earth embankments, river banks etc. The work described involved identification of wave modes present, derivation of dispersion curves to describe propagation behaviour and evaluation of experimental data to explain mode conversions and interactions with interfaces observed in the results. [Copyright &y& Elsevier]

The objective of this paper is to investigate geometric and material parameters that affect the interaction of multiple pre-existing (initiated) cracks due to rolling contact fatigue (RCF) loading conditions. In particular, the behaviour of short cracks (head checks) in railway rail is studied. Parameters of interest are initial crack angle and spacing, distribution of initial crack lengths, width of the load/contact zone, and the material properties (in particular, the friction coefficient). Furthermore, the sensitivity of the finite element (FE)-mesh density is investigated. An open question of particular interest is the effect of crack interaction, e.g. shielding, on the prevailing crack spacing. In view of all uncertainties of the material model as well as the three-dimensional geometric complexity of the RCF problem, it is important to obtain a good understanding of the sensitivity of parameter changes. This is achieved in the presented investigation, although it is carried out using simplifying assumptions such as plane strain, linear elasticity, and Hertzian pressure distribution. [ABSTRACT FROM AUTHOR]

Abstract: Short-pitch rail corrugation developing on the low rail in sharp curves is a problem experienced by many railway networks worldwide. Because of the large existence of small radius curves, metro lines are particularly affected. This case study is performed as part of a project which aims at developing a numerical tool for prediction of rail corrugation growth on curves. The development of corrugation on a 120m radius curve of the Stockholm metro has been monitored by repeated measurements of rail roughness and train pass-by noise. Within a grinding interval of 1 year, severe short-pitch corrugation was build up with maximum peak-to-peak magnitudes of about 0.15mm. Spectral analysis of measurement data shows large roughness magnitudes in the wavelength interval 4–14cm, with peaks at approximately 5cm and 8cm. The corrugation pattern has a pure longitudinal direction (with corrugation ridges transverse to the track direction) and an irregularly varying magnitude along the 100m long measured track section. The roughness growth rate increased with time until 300 days after rail grinding, thereafter only moderate additional roughness growth was observed. Because of moderate train speeds of about 30km/h, the rolling noise caused by the corrugation has a low-frequency content (<200Hz). A 10.1dB unit increase (139–300 days after grinding) in roughness level in the wavelength interval 4–14cm was found to correspond to an increase in rolling noise level in the frequency interval 60–200Hz of 4.9dB. In dry weather conditions, discomfort related to pass-by noise is rather linked to the occurrence of wheel squealing than to rolling noise. [Copyright &y& Elsevier]

Abstract: The coupling relationship between oblique fatigue crack and rail wear in curve track was investigated by means of field analysis and theoretical calculation. The field investigations indicate that while the side wear of rail is serious, the fatigue crack is relatively slight. The increase of rail wear rate can alleviate its fatigue damage. The relationship between side wear of rail and fatigue crack damage seems as competitive and restrictive coupling mechanisms. Thus, a new asymmetrical rail grinding method was developed to prevent oblique crack damage of curve track in Guangzhou–Shenzhen railway. The field test results indicate that the asymmetrical rail grinding increases the guidance force between wheel flange and rail and aggravates rail wear. This new rail grinding method can dramatically alleviate rail fatigue oblique crack damage in high-speed curve track by increasing artificially wear rate. [Copyright &y& Elsevier]

Torsional vibrations of metro wheel sets are known to be involved in the wavelength-fixing mechanism of the rutting-type rail corrugation. In the first part of this paper, the basic conditions for this type of wear to appear are established using a theory developed in the frequency domain. The efficiency of a dynamic vibration absorber tuned to the first torsional resonance of the wheel set to mitigate rutting corrugation is evaluated numerically. In the second part, the phenomenon is studied on a quarter-scale test bench. The scaling laws for wheel-roller wear predictions are established. The efficiency of the dynamic vibration absorber is evaluated on the scaled bench. The results are compared with theoretical predictions from a linear model. Additionally, the measurements are compared with numerical results from a multi-body model portraying the experiment. [ABSTRACT FROM AUTHOR]

Abstract: High-speed ACFM tests were carried out using a rotary test piece that contained spark-eroded notches. The ACFM sensor detected the induced notches during inspection at 121.5km/h. The recorded signal remained unaffected by the increases in inspection speed under constant lift-off. To simulate actual rail inspection conditions at high speed, further tests were carried out using a spinning rail rig and a set of rails that contained spark-eroded notches of various shapes and sizes up to a speed of 32km/h. Although, the ACFM sensor successfully detected the majority of the notches, the signal obtained was affected by lift-off variations. [Copyright &y& Elsevier]

Numerical simulations are performed to study plastic deformation and fatigue impact of an insulated joint. The simulations feature a sophisticated constitutive model capable of capturing ratcheting under multi-axial loading conditions. Calculation results are presented in the form of effective strain magnitudes, plastic zone sizes, and multi-axial low cycle fatigue parameters. The simulation results indicate that the main damage mechanism at insulated joints is ratcheting and not low cycle fatigue. A parametric study quantifies effects of increased vertical and longitudinal load magnitudes, as well as the effect of an increased insulating gap. In particular, longitudinal loading is indicated as being severely deteriorating for the rail in the vicinity of the joint. Finally, the effect of rail edge bevelling is assessed and found to be small for the case studied. [ABSTRACT FROM AUTHOR]

A study assessing vertical track geometry quality based on simulations of dynamic track-vehicle interaction is presented in this article. The dynamic model is composed of track, vehicle, and wheel-rail contact with moving irregularities and is solved in the frequency domain by fast Fourier transform or in the time domain by constructing a filter function based on system identification. Frequency-dependent stiffness and loss factor of railpads are used in this study. Numerical simulations are carried out for a 120km long track to demonstrate the potential benefits of enhancing track quality assessment by calculating wheel-rail forces. [ABSTRACT FROM AUTHOR]

Rails are systematically inspected for internal and surface defects using various nondestructive evaluation (NDE) techniques. During the manufacturing process, rails are inspected using automated optical cameras and eddy current sensing systems for any surface damage, while the presence of internal defects is assessed through ultrasonic inspection. Similarly, ultrasonic transducers and magnetic induction sensors have been extensively used by the rail industry for the inspection of rails in-service. More recently, automated vision techniques and hybrid systems based on the simultaneous use of pulsed eddy current probes and conventional ultrasonic probes have been introduced for the high-speed inspection of rail tracks. Other NDE techniques, such as electromagnetic acoustic transducers, laser ultrasonics, guided waves, and alternating current field measurement probes, are also under development for application in the rail industry. This paper comprehensively reviews NDE methodologies in use around Europe and North America for rail defect detection. This includes a detailed overview of the background theory and the techniques used to incorporate condition data into maintenance procedures. It also presents a review of the current state-of-the-art in NDE of railways coupled with a discussion of future developments and novel inspection methodologies in the field. [ABSTRACT FROM AUTHOR]

The results of experimental investigation of railway wheel failures and strength anisotropy due to rolling contact fatigue are presented. The results indicate that plasticity acts to concentrate regions of intense hardening near the edges of contact. The determination of overall mechanical properties of small-scale volumes frequently relies on the indentation technique. Strength characteristics of the wheel material were investigated by dynamic indentation method and portable dynamic indentation tester was used for hardness measurements. It was found that some characteristic force values of the instrumented hardness test are very well correlated to tensile strength. [ABSTRACT FROM AUTHOR]

Issues of detection of flaws in the railhead by the echo and mirror methods are considered. The influence of the degree of rail wear on the path of propagating ultrasonic beams has been studied. It has been shown that, owing to multiple reflection of ultrasonic beams inside the railhead, transverse cracks can be reliably detected on both the working and nonworking faces of the railhead. Computer-simulation-based calculations are confirmed by data on detection of actual flaws in the railhead. The results are used in the development of sounding systems for AVIKON-type multichannel demountable ultrasonic flaw detectors for total inspection of rails. [ABSTRACT FROM AUTHOR]

Recent train accidents have reaffirmed the need for developing rail defect detection systems that are more effective than those used today. One of the recent developments in rail inspection is the use of ultrasonic guided waves (UGWs) and non-contact probing techniques to target transverse-type defects. Besides the obvious advantages of non-contact probing, that include robustness and a potential for large inspection speed, such a system can theoretically detect transverse defects under horizontal shelling or head checks. This paper demonstrates the effectiveness of digital signal processing to enhance the damage detection sensitivity of the non-contact system. The method proposed here combines the advantages of UGW inspection with the outcomes of the Discrete Wavelet Transform (DWT) that is used for extracting robust defect-sensitive features. In particular, the DWT is exploited to de-noise the ultrasonic signals in real-time and generate a set of relevant wavelet coefficients to construct a uni-dimensional damage index. The general framework proposed in this paper is applied to the detection of crack-like and internal defects in a railroad track mock-up built at UCSD. The proposed signal analysis approach is general and is applicable to many other structural monitoring applications using UGWs as the main defect diagnosis tool. [ABSTRACT FROM AUTHOR]

Defects in rails caused by rolling contact fatigue (RCF) are of growing concern to the railway industry. Conventional ultrasonic inspection methods are often not reliable in detecting critical RCF defects. The aim of this work was to develop a reliable screening tool that discriminates between critical and tolerable defects and therefore complements the existing inspection methods. The method presented here employs ultrasonic surface waves which propagate several metres along the railhead. They are excited by a local immersion probe which is operated in pulse-echo mode and scanned along the rail; in practice this would be done using a wheel probe. The excitation frequency was chosen to be around 200 kHz at which there exists a suitable surface wave mode with a sufficient penetration depth. A spatial averaging technique is applied to suppress unwanted guided wave modes and reduce signal complexity. The method has been tested successfully on a number of specimens containing artificial and real defects. [ABSTRACT FROM AUTHOR]

As part of a research that led to the development of the performance-based track geometry (PBTG) inspection technology, the Transportation Technology Center, Inc., Pueblo, CO, USA, a wholly owned subsidiary of the Association of American Railroads, has developed a technique relating track geometry to vehicle performance, real-time. This technique is based on the neural network (NN) approach, an emerging powerful tool in recognizing complex patterns and non-linear relationships between many inputs and an output, such as the relationship between track geometry and vehicle response. On the basis of this technique, many NNs have been developed (trained) from actual vehicle/track interaction test results. For a given vehicle type, the trained NNs directly relate three-dimensional track geometry and vehicle operating speed to vehicle performance. The effects of other track conditions such as lubrication, rail profile, and track stiffness are indirectly considered on the basis of their statistical distributions from test results. Because the PBTG inspection is intended to optimize the track geometry maintenance, the vehicle types selected for testing to date were the ones most sensitive to track geometry (in North America, these are the tank car, covered hopper car, and coal gondola car). However, more NNs for other vehicle types can be easily trained on the basis of the NN technique developed using actual vehicle performance and track geometry test results. [ABSTRACT FROM AUTHOR]

A technique is described to measure the spatial variation of rail temperatures with a view to highlighting sections of railway track prone to buckling in extreme temperatures. Thermal maps of a section of test track were produced by equipping a personnel carrier with a thermal imager and global positioning system (GPS). Temperature readings were taken using the rusted web (side) of the rail so that emissivity could be assumed constant. The results indicate that much of the spatial variation in daytime rail temperature can be explained by shading effects, with exposed sections of track on embankments being consistently the warmest and, therefore, the most prone to buckling. It is envisaged that the technique could be used to forecast the problem areas and will ultimately provide useful verification data for spatial modelling studies. [ABSTRACT FROM AUTHOR]

Presents information on a possible mechanism for rail dark spot defects. Information on rail dark spot defects; Details on the occurrence of dark spots; Look at the features of dark spot defect.

The performance of existing ultrasonic and magnetic flux leakage techniques in detecting rail surface-breaking defects such as head checks and gauge corner cracking is inadequate during high-speed inspection, while eddy current sensors suffer from lift-off effects. Early detection of such rail defects is of paramount importance since a single crack can potentially lead to fatigue failure. The results obtained through rail inspection experiments under simulated conditions using an alternating current field measurement (ACFM) micro-pencil probe suggest that this technique can be applied for the accurate and reliable detection of surface-breaking defects at high inspection speeds. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editor discusses various reports published within the issue, including one on the problem of flaw detection in aluminum castings, another on a hybrid model for leak detection in gas pipelines, and the use of visual-based techniques in the detection of squat flaws in railway rails.