Academic literature on the topic 'Railroad rails Steel'

Railway travel safety is an important component in rail transportation. The reliability of the railroad infrastructure is one of the points to support the safety of railroad operations. Lintas Bandung - Cikampek is a cross that has varied geographical contours where right-left rail roads have hills and slopes so that the area between Purwakarta Station - Ciganea Station is a landslide-prone area. As happened in the field there was an avalanche at KM 107 + 100 - KM 107 + 300 which caused disruption to train travel. In addition, improper handling of landslides will cause other potential dangers. The handling of the landslide slope in KM 107 + 100 - KM 107 + 300 uses steel tape from the used rails because the landslide is considered to be less than optimal and is looking for other ways to handle landslides. looking for comparisons compared to using the shotcret method. In this study, we tested the landslide handlers that have been carried out by comparing the handling carried out in accordance with the existing provisions between the steel plaster method of the rail used with the shotcrete method. The cause of landslides is due to a steep angle of 65⁰ with a peak height of 15 meters. The impact on crossing is applied to taspat 5 km / hour to anticipate sudden landslides. From the results of the analysis, it was found that the shotcrete method was considered capable of handling landslide-prone areas in KM 107 + 100 - KM 107 + 300. However, for the handling that had been carried out using steel plaster from used rails. However, this handling is considered not optimal because of the limited number of rails around vulnerable areas, resulting in plaster walls that can still make material exit to the railroad tracks.

The railway lines are an integral construction made of steel, concrete or other construction are located on the surface, below and above ground or dangling along with devices that direct the course of the train. Reflecting on the success of the revitalization of the railway line Padang-Pariaman, PT. Railway DIVRE II West Sumatra recently returned to the revitalization of the railway line Lubuk Alung–Kayu Tanam. In this final project feasibility analysis back to the road construction railroad Lubuk Alung-Kayu Tanam considering this path has not been used and an increase in the construction of the railroad on the route. The methodology used is the collection of data from related parties subsequently perform the calculation and analysis of railroad construction that has been revitalized. Data obtained from the calculation of the voltage rails on existing condition of 1380.34 kg/cm2 and the voltage rails after revitalized by 840.601 kg/cm2 while rail voltage maximum allowed is 1325 kg/cm2, the rail existing deserves to be revitalized. Iron bearing on the condition of the existing able to withstand a load of 6761.69 kg, while the load caused by railbus is 8568.986 kg so that the iron bearing existing not worth traversed railbus axle 18 ton and made improvement to the concrete pads. After upgrading, held their concrete pads capable of 23241.678 kg load and expenses incurred as a result of railbus axle 18 tons of concrete pads amounted to 6986.276. Concrete pads so deserve to be passed railbus axle 18 tons. The results of this thesis states that the construction of a rail road Lubuk Alung-Kayu Tanam deserves to be revitalized because of the condition of the existing construction rails and bearings are not able to withstand the stresses and loads that occur due railbus 18 tons passing through.

Two new technologies have recently been developed that can help to solve some of the wheel rail contact problems. The first is a method of top of rail lubrication (TOR) or friction modification (FM). The second is a technique of laser glazing of steel rails. Both technologies help in reducing the friction, wear, and energy consumption in the wheel rail contact. This paper introduces the two technologies and presents some specific aspects of both methods. A 1:12 scale wheel/rail simulator (LA 4000) was used to study the potential of these two new technologies on energy savings. In order to develop an efficient top of rail lubrication system, all parameters affecting FM consumption rates have been studied. These parameters include speed, angle of attack, load and lubricant quantity. LA 4000 friction/wear studies were conducted to evaluate the effect of laser glazing and TOR lubricant on the lateral slip forces between a simulated wheel/rail. Three conditions under dry and lubricated environments were studied: unglazed wheel and an unglazed rail, an unglazed wheel against a glazed rail, and a glazed wheel against a glazed rail. The results of the tests indicate that the use of TOR and laser glazing does indeed reduce the lateral forces, which are an indirect measure of the damage caused to the wheel, rail and track.

Train is the main mode of transportation that we often use, the train itself can be used as a tool for shipping goods and mobilizing passengers, this transportation is very unique and has its own path in the form of steel strings across from hundreds of kilometers, railroad bearing structures currently exist which uses concrete and wood, the railroad is very vital and is an important supporting facility. The process of railroad monitoring is complex and complicated, takes a long time, the previous method is simple and conventional by tracing the railroad tracks manually or using a geometric gauge mounted direl or also known as railpod, railpod will follow the rails and will provide report if there is a train track that is damaged, broken or shifted, this research will create an image-based monitoring system using drones as a track monitor, another way is to take pictures using satellite data that will provide clear information about road conditions before being passed by the train, the railroad data processing system by using image processing can display visual responses up to cm in size, the response appears if there is a shift in the path then the system directly provides data in the form of location and shifting paths on the main computer, this system is more c eTat in checking and analyzing train track data with high accuracy and precision up to 90%, in addition to imagery from satellite images can use drones, drones themselves are very easy in maintenance and use and are able to cut production costs and even workplace accidents in the field workers themselves can be avoided because the drone is able to reach the track and railroad that is difficult for example through the tunnel or the railroad track along the hills and densely populated.

Thesis (MScEng)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: The Tubular Track (TT) railway system is a twin beam modular railway system consisting of two reinforced concrete (RC) beams on which steel rails are continuously supported. The beams are linked with galvanised steel gauge tie bars and continuously supported by soil foundations, and can be used to replace conventional sleeper and ballast railway support. The TT railway system has in the past been analysed with various analysis methods, but were found to obtain con icting results. The con icting results means that one of the analysis methods used for the analysis and design of TT railway sections is either an underestimation or overestimation of section displacements, forces, and stresses; or both methods could even be incorrect. The main emphasis of this investigation is therefore to develop and verify static and dynamic analysis methods and modeling techniques which can be used to simulate the TT railway system accurately. The results and models of the previous analyses are not explicitly investigated in this dissertation, but serve as a motivation for this investigation. The TT system is supported by several soil strata providing vertical support, but geometrically modeling the subgrade strata in the analysis models adds a high level of complexity, and is not feasible for general analysis where soil conditions are mostly unknown. The elastic foundation theory is therefore used to accurately simulate the interaction between beam and foundation and therefore su ciently simpli es the analysis models. Simpli cation of a subgrade foundation by simulating a soil sti ness supporting the TT beam is investigated and analysed by comparing nite element analysis (FEA) results of various soil models using parameters of four known soil formations currently in use at TT railway sections. The FEA of the subgrade formations indicates that there is a linear relationship between the modulus of subgrade reaction for a square plate bearing test and a rectangular, in nitely long plate representing the subgrade support for the TT beams. A square plate bearing test can therefore be performed on site and modi ed to represent the actual subgrade support sti ness of the TT railway structure, whereafter it can be used for the analysis and design of the TT system using one of the proposed analysis methods. The analysis models used range from simple theoretical models based on elastic foundation principles, to two-dimensional (2D) beam elements, and ultimately to complex three-dimensional (3D) solid nite element models. The models used for the analyses are the Single and Double Beam elastic foundation, PROKON 2D beams, ABAQUS 2D beams and ABAQUS 3D solid element models. The alternative analysis methods considered should provide a clear indication of which analysis methods are accurate and feasible for design of the TT system. An in-situ reference model with known de ections and design parameters speci c to a TT railway section is used to analyse the di erent analysis methods' accuracy and validity. The Double Beam, ABAQUS 2D and ABAQUS 3D models were found to provide very similar displacements, bending moments and shear forces for a static analysis, whereas the PROKON and Single Beam models provide unsatisfactory results. The PROKON beam model underestimates the bending moments and shear forces in the rail, and overestimates bending moments and shear forces in the RC beam by a considerably margin. This result can lead to the underdesigning of the rail which could possibly force the RC beam to be subjected to larger maximum bending moments and shear forces than for what it was originally designed for, thereby nullifying or possibly even exceeding the amount for which it was overdesigned. This e ectively accelerates material fatigue, which might be the possible cause of the small cracks in the RC beams which have been found on some TT railway sections, which is currently being investigated. A graphical user interface of the Double Beam method is provided for quick and e cient analysis. Empirical methods used to simulate the dynamic nature of a railway system are often used in the industry to simplify the dynamic loading by determining a dynamic amplitude factor (DAF) to be applied to a static load. An implicit dynamic FEA is therefore performed to obtain the DAF for the reference section, which is subsequently used for the comparison with in-situ de ection results. The results of dynamic analysis validates the proposed empirical analysis method, as the displacements obtained were very similar to actual eld test results, thereby also verifying the accuracy of the proposed analysis methods. The sensitivity of the TT system to design parameters is also investigated to indicate to which parameters the design is sensitive to and where small variations of these parameters require due consideration for future and analysis of the TT railway system.
AFRIKAANSE OPSOMMING: Die Tubular Track (TT) spoorweg stelsel is 'n dubbel balk modulêre treinspoor sisteem bestaande uit twee gewapende beton balke waarop staal spore voortdurend ondersteun word. Die balke word gekoppel deur gegalvaniseerde staal stawe vir laterale styfheid en word deurlopend ondersteun deur grond fondamente, en kan gebruik word om konvensionele dwarslêer en ballast spoorweg ondersteuning te vervang. Die TT spoorweg stelsel was in die verlede met verskeie analiseringsmetodes ontleed, maar het teenstrydige resultate gewerf. Die teenstrydige resultate beteken dat een van die analise metodes wat gebruik word vir die analisering en ontwerp van TT spoorweg seksies 'n onderskatting of oorskatting van verplasings, kragte, en spannings is; of beide metodes kan selfs verkeerd wees. Die hoofklem van hierdie ondersoek is dus die ontwikkeling en veri kasie van statiese en dinamiese analitiese metodes en modellering tegnieke wat gebruik kan word om die TT spoorweg stelsel akkuraat te simuleer. Die resultate en modelle van die vorige ontledings word nie uitdruklik in hierdie proefskrif ondersoek nie, maar dien as 'n motivering van hierdie ondersoek. Die TT stelsel word ondersteun deur verskeie grond strata wat vertikale ondersteuning verskaf, maar meetkundige modellering van die grond strata in die ontledingsmodelle veroorsaak 'n hoë vlak van kompleksiteit wat nie bruikbaar is vir algemene analises waar grondeienskappe meestal onbekend is. Die elastiese fondament teorie word daarom gebruik om die interaksie tussen die balk en die fondament akkuraat te simuleer, en vereenvoudig dus die analitiese modelle voldoende. Vereenvoudiging van 'n grond fondament deur 'n grond styfheid ondersteuning van die TT balk te simuleer is ondersoek en ontleed deur die resultate van eindige element analises van verskillende grond modelle te vergelyk. Bekende ontwerp parameters van vier bekend grondformasies wat tans gebruik word by TT spoorweg seksies word vir hierdie analises gebruik. Die eindige element analises van die grondformasies dui daarop aan dat daar 'n lineêre verwantskap tussen die modulus van grond reaksie vir 'n vierkantige plaat dratoets en 'n reghoekige, oneindige lang plaat dratoets bestaan. 'n Vierkantige plaat dratoets kan dus op terrein uitgevoer en aangepas word om die werklike styfheid van die grond ondersteuning van die TT spoorweg sisteem voor te stel. Die analitiese modelle wat gebruik word wissel van eenvoudige teoretiese modelle wat gebaseer is op elastiese fondament beginsels, twee-dimensionele (2D) balk elemente, asook komplekse driedimensionele (3D) soliede eindige element modelle. Die modelle wat gebruik is vir die ondersoek is die Enkel en Dubbel Balk elastiese fondament, PROKON 2D balke, ABAQUS 2D balke en ABAQUS 3D soliede element modelle. Hierdie reeks bied 'n duidelike aanduiding watter analiseringsmetodes akkuraat en haalbaar is vir die ontwerp van die TT stelsel. 'n In-situ verwysingsmodel met bekende de eksies en ontwerp parameters wat spesi ek is vir 'n TT spoorweg seksie word gebruik om die akkuraatheid en geldigheid van die verskillende analitiese metodes te analiseer. Die Dubbel Balk, ABAQUS 2D en ABAQUS 3D modelle verkry baie soortgelyke verplasings, buigmomente en skuifkragte vir 'n statiese analise, terwyl die PROKON en Enkel Balk modelle onbevredigende resultate verkry. Die PROKON model onderskat die maksimum buigmomente en skuifkragte in die staal spoor, en oorskat buigmomente en skuifkragte in die gewapende beton balk. Hierdie resultaat kan moontlik lei tot die onderontwerp van die staal spoor en dwing moontlik vir die gewapende beton balk om blootgestel te word aan groter buigmomente en skuifkragte as vir wat dit oorspronklik ontwerp is, en verontagsaam sodoende moontlik die kragte waarvoor dit oorontwerp is. Dit versnel e ektief materiaal vermoeiing, wat die moontlike oorsaak is van die klein krake wat gevind is in die gewapende beton balke op sommige TT spoorweg seksies wat tans ondersoek word. 'n Gra ese gebruikerskoppelvlak van die Dubbel Balk model is verskaf vir vinnige en doeltre ende ontleding. Empiriese metodes om die dinamiese aard van 'n spoorweg-stelsel te simuleer word dikwels gebruik in die bedryf om dinamiese belasting te vereenvoudig deur middel van die gebruik van 'n dinamiese amplitude faktor (DAF) wat op 'n statiese belasting aangewend word. 'n Implisiete dinamiese eindige element analise word dus uitgevoer om die DAF te ondersoek, wat daarna gebruik word vir die vergelyking met die in-situ de eksie resultate van die in-situ verwysingsmodel. Die resultate van die dinamiese analise bevestig dat die voorgestelde empiriese analise metode gebruik kan word, omdat die verplasings wat verkry baie soortgelyk was aan werklike veld toets resultate, en daardeur ook die veri ëring van die akkuraatheid van die voorgestelde analise metodes bewerkstellig. Die sensitiwiteit van die TT stelsel vir ontwerp parameters word ook ondersoek om aan te dui watter parameters die ontwerp voor sensitief is, en waar klein variasie in hierdie ontwerp parameters behoorlike oorweging vereis vir die toekomstige analisering en ontwerp van die TT spoorweg stelsel.

M.Ing.
The aim of Spoornet is to provide a minimise predictable service. In order to provide a predictable service, it is necessary to move trains safely and effectively from the place of departure to their destination. The keywords here are safely and effectively. Although support functions such as infrastructure and train control procedures are vital in moving the train, the train or rolling stock as it is generally known, warrants some attention. Defects on the rolling stock are very costly to Spoornet. This is mainly due to the fact that a defect on the rolling stock that goes undetected can cause damage to the rolling stock and the infrastructure. This damage can eventually lead to derailments. Considering that a derailment can cost Spoornet millions of rand and cause delays to the services, it is only logical to spend time preventing derailments. It is for this reason that a workgroup was formed to investigate and solve the problem of defects causing derailments and delays by developing an early warning system. The need for an integrated train condition monitoring system became apparent when considering an early warning system. The objectives of the integrated train condition monitoring system are to provide train condition information to different users, and alarms on detection of emergency or dangerous conditions. Various train defects that may cause damage or derailments were identified. One of them being a flat wheel on a rail vehicle. A flat wheel is characterised by the flattening of the wheel on one or more positions on its circumference, so that the wheel does not have an even and completely round profile. Flat wheels are mostly caused by the wheels of a vehicle becoming locked during braking, and sliding along the rail track. The friction created by this action grinds a flat spot on the wheel. The flat wheel leads to a decline in the riding quality of the rolling stock and a rise in the levels of vibration and noise is evident. But more importantly, the flat spot causes the wheel to roll unevenly, creating impacts on the rail on some points. It is these impacts that can cause damage to the rail and the rolling stock. Depending on the length of the flat spot, the vehicle type and speed, the stresses may be sufficient to cause final failure of the rail or initiate fatigue cracks in the rail. Severe flat wheels are a safety hazard and can in some cases, cause derailments and consequent delays to trains. Smaller flat spots contribute to track deterioration and so increase maintenance costs by damaging the rails, sleepers and ballast. Flat wheels can thus be very costly to Spoornet and its public image. In addition to safety and economic considerations, wheel flats reduce the comfort levels in the passenger coaches and the noises they make is annoying. In an attempt to restrict the damage caused by flat wheels, most railway administrations place a limit on the length of the flats that may stay in service. But to effectively find a flat wheel on rolling stock is currently a very expensive exercise. Flat wheels can be detected by an audible knocking sound when standing next to the rail. This sound is impossible for the driver to hear and therefore goes undetected. Normally flat wheels are detected by random inspection of the rolling stock or when they are brought in for a routine service. The service cycle on rolling stock can be up to 24 months in Spoornet. Considering that a flat wheel has an impact roughly every 3m, a serious flat generates roughly 160 000 impacts on a single trip on the coal heavy haul export line. It is therefore clear that a flat wheel can cause a considerable amount of damage between service cycles. The severity of the problem is however not accurately defined in Spoornet, because up to a few months ago there was no detection system in use to determine the distribution of flat wheels. The research department of the Deutsche Bundesbahn however considers rail fractures due to the flat wheels to be a serious problem with a significant annual replacement cost. There are thus sound safety and economic reasons for wishing to understand the mechanisms of flat wheels and to develop an early warning system using an automatic detector.

This chapter describes the development of the Bessemer steel process. In spring 1862, a rail of Bessemer steel was laid down between two abutting iron rails in the Camden yard of the London and Northwestern Railway. Three years later, in May 1865, the first rail manufactured from Bessemer steel in the United States was produced at the North Chicago Rolling Mill. The chapter first provides an overview of steelmaking and metallurgy before discussing the commercial and intellectual development of the Bessemer steel process, along with the use of Bessemer steel in making railroads. It also considers innovations in the production of the Bessemer steel process and the patent controversy sparked by the technology, tariff protection for the process, and the Bessemer Association's price-fixing scheme. The chapter concludes by highlighting the stages involved in the innovating process: the inventive stage, the stage in which the invention is applied by the first entrepreneurs, the stage in which other entrepreneurs and engineers refine and consolidate, and the stage in which still other entrepreneurs take over to expand.

Indian Railways is the largest rail network in the world, can be plays an essential role in the development of infrastructure areas such as coal, electric power, steel, concrete and other critical industries. Indian government has started concentrating on the modernization of the railways through huge investment. Internet of Things(IoT) is vital attention to expansion and excellence. The chapter will commence with the past history of rail transport in India Further section will support the IoT which is another great trend in technology. The later section of the chapter will give attention to how Internet of things could expertise the railroad industry, introducing a remedy which will be made to modernize aging sites at railroads, improve basic safety. The railway can help the passenger to utilize fewer interruptions in the event that's what they need. There's a large number of things that require to be watched and the railway can run as a completely digital service, without having to have people walking the tracks, it brings cost benefits and increased safety for the workforce.

Higher requirements of efficiency on railroad systems have set off (among other measures) higher axle load on rails. The increase in axle loads can contribute to a series of defects on perhaps the most unappreciated component of a railroad system. Higher axle loads can lead to excessive wear, fatigue and ultimately fracture of the steel rails. Therefore to answer the challenge demanded by the increase in axle loads the development of high performance steels for rail applications is of primary importance. A research program to study the microstructural aspects of near-eutectoid steels with improved mechanical properties and wear resistance was recently completed. The new high performance rail steels were developed through a combination of advanced alloy design-thermomechanical processing-and-controlled cooling. The mechanical properties exhibited by the new steels have exceeded the AREMA requirements for this type of rail steel application. The wear resistance of the newly developed steels was evaluated and the results obtained compared to commercial rails were superior under the testing conditions used in this study. The alloy design philosophy, thermomechanical processing and properties of the new steels will be presented and discussed in this paper.

The Federal Railroad Administration (FRA) routinely conducts investigations of railroad accidents to determine causation and any contributing factors to help the railroad industry implement corrective measures that may prevent similar incidents in the future. Over the past decade, FRA has investigated multiple broken rail accidents in which fractures in the rail web were identified. The common features observed in the recovered rail fragments from these accidents included welds and spots or burn marks on the web, indicating that the rails were joined together by pressure electric welding. Pressure electric welding uses a welding head that clamps around two opposing rail ends, pressing an electrode on each rail, then hydraulically pulling the rail ends together while arcing current through the electrodes into the rails, causing them to essentially melt together to form a continuous rail. Based on the similarities observed in the web fractures, FRA rail integrity specialists hypothesized that stray (i.e. inadvertent and unwanted) arcing during pressure electric welding can result in the formation of burns or pits on the rail where it makes contact with the electrodes. Moreover, these electrode-induced pits behave as stress raisers (also referred to as stress concentrations). Fatigue cracks often develop at locations of stress concentration. Once a fatigue crack initiates, the localized stress encourages the growth of the crack, which may potentially lead to rail failure. This paper describes the forensic evaluations of three railroad rails containing electrode-induced pitting. These evaluations include: magnetic particle inspection to nondestructively detect cracks emanating from the pitting; fractography to study the fracture surfaces of the cracks; metallography to study the microstructure; analysis of chemical composition; and measurements of tensile mechanical properties and fracture toughness of rail steel. Moreover, the results of these evaluations confirm the hypothesis postulated by FRA that stray arcing during pressure electric welding can cause electrode-induced pitting.

The Federal Railroad Administration (FRA) has been sponsoring research on rail integrity for several decades. This research has been chiefly managed and conducted by the Volpe National Transportation Systems Center (Volpe). Particular focus has been given in this research to rail head defects, known as detail fractures, since they are the most commonly encountered defect in continuous welded rail track [1]. Testing and analyses have been performed on railroad rails manufactured without head hardening. Modern rail, however, are now heat treated during the manufacturing process to harden the rail surface to increase its resistance to wear. As such, the heat treatment and nonuniform cooling induce complex residual stress patterns in the rail that can affect microstructure and fatigue crack growth rate behavior. This paper will describe research to examine defect growth behavior of modern rail steels. This research is a collaboration among several organizations: Thornton-Tomasetti, Arcelor-Mittal, Lehigh University, Harvard University, National Institute of Standards and Technology (NIST), Fraunhofer Institute, and Volpe. Arcelor Mittal donated rails with different grades of steel: advanced head hardened, head hardened, and standard strength (i.e. non-head-hardened). Lehigh conducted laboratory tests on specimens cut from these rails to perform various tests, which include: hardness measurements, mechanical testing to measure tensile properties, fracture toughness measurements, and fatigue crack growth rate tests. All of these tests were performed in accordance with applicable ASTM International standards. NIST and Fraunhofer performed preliminary neutron diffraction measurements of residual stresses on the different rails. Moreover, this paper will present results from the laboratory testing program. Implications of these results on detail fracture growth behavior will also be discussed.

This paper describes work in-progress that applies the finite element (FE) method in predicting the responses of individual railroad crossties to rail seat pressure loading in a ballasted track. Both wood and prestressed concrete crossties are examined. The concrete tie is modeled as a heterogeneous medium with prestressing wires or strands embedded in a concrete matrix. The constitutive relations employed in the models are: elasticity followed by damaged plasticity for the concrete material, linear elastic bond-slip relations with potential initiation and evolution of damage to the bond for the steel-concrete interfaces, orthotropic elasticity followed by failure dictated by orthotropic stress criteria for the wood ties, extended Drucker-Prager plasticity for the granular and frictional ballast material, and elastic half space for the subgrade. The corresponding material parameters are obtained from the open literature. Under a simplified pressure load uniformly distributed over the rail seat area, the FE method predicts tensile cracking at the tie base below the rail seats of a concrete tie and compressive failure in the rail seats of a wood tie. The rail seat force-displacement relations are obtained from the simulations. The resultant rail seat forces at which tie failures occur are compared for concrete and wood ties. The FE method appears to be a promising tool for studying the railroad tie behavior under rail seat loading conditions in a ballasted track. Experimental data will be sought to calibrate the material parameters and verify the modeling approach. Additional track components, particularly rails, rail pads and fasteners, will be incorporated in future modeling efforts. This detailed modeling approach may help to shed light on the rail seat deterioration failure mechanisms observed in some concrete ties.

The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, in pair with a real-time statistical analysis algorithm, is being developed. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. This system requires a specialized filtering approach due to the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Experimental tests have been carried out at the UCSD Rail Defect Farm. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. A field test will be planned later in the year to further validate these results. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.

The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail defect detection. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, paired with a real-time statistical analysis algorithm, has been realized. This system requires a specialized filtering approach based on electrical impedance matching due to the inherently poor signal-to-noise ratio of air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. The system’s operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. The prototype based on this technology was tested in October 2014 at the Transportation Technology Center (TTC) in Pueblo, Colorado, and again in November 2015 after incorporating changes based on lessons learned.

Railroad wheels guide a freight car along the rails while supporting mechanical loads, and also serve as the brake drum in the air brake system of a freight car. Since a 36-inch diameter freight car wheel experiences approximately 560 revolutions per mile, and since many North American freight cars accrue 100,000 miles per year in service, fatigue properties of steel are very important. Further, elevated tread temperatures resulting from tread braking are known to significantly reduce the yield strength of the wheel steel at the tread surface. This paper describes fatigue testing of AAR rim quenched Class C wheel steel manufactured with microalloy additions. Small amounts of selected alloy elements were purposely added to develop a wheel steel with improved high temperature yield strength. Rotating bending fatigue tests, conducted at a well-known professional testing laboratory, were performed at ambient and elevated temperatures using complete stress reversal (R = -1) cycling. Stress-life (S-N) curves were constructed and the microalloy steel results were compared to existing fatigue data, and to results for typical Class C steel with no microalloy additions. Past research work is briefly reviewed. Test results are discussed with emphasis on the implications for service performance of wheel steel.

Abstract The most common rail defect encountered in continuously welded rail is known as the detail fracture. The U.S. Department of Transportation, Federal Railroad Administration has sponsored and managed research over the past several decades to understand the structural integrity of rail in general, and the fatigue crack growth behavior of detail fractures in particular. Control of rail integrity and defect growth is conducted via periodic rail tests (i.e. inspections) to ensure that rail defects do not become large enough to cause rail failure. Moreover, federal regulations have been codified to establish a maximum interval between rail inspections based on the results of government-sponsored research. Over the past several decades, however, rail manufacturing has evolved and improved, particularly the head-hardening process to improve wear resistance. Propagation life of railroad rail was examined in previous research using fatigue crack growth data for non-head-hardened rail. Recently Thornton-Tomasetti conducted research, sponsored by FRA, to examine the fatigue crack growth behavior of modern rail steels (i.e. railroad rails with head-hardening). The initial results of the more recent research effort were reported in the 2019 Joint Rail Conference. In this paper, fatigue crack growth rate data generated for head-hardened rail are used to examine the fatigue crack growth life of detail fractures under nominal revenue service conditions. Moreover, this paper applies a probabilistic approach to estimate rail life to account for the inherent variability or scatter typically observed in fatigue crack growth rate data. Regression methods are employed to derive the parameters for the Walker crack growth rate equation, which are subsequently treated as correlated, multivariate, and normally distributed random variables. Data from four different rail steels are used in the regression analyses, which are referred to as: Advanced Head Hardened (AHH), Head Hardened (HH), Standard Strength (SS), and Colorado Fuel and Iron (CF&I). Monte Carlo simulations of fatigue growth of detail fractures are carried out to estimate fatigue life distributions for each of the different rails. The results from these four rail steels are compared to those based on the previous research for non-head-hardened rails. Implications of these comparisons on determining rail testing intervals are discussed.

Early failure of pre-stressed concrete railroad ties in the field is a costly occurrence with modern ties. A key predictor of the performance of a pre-stressed concrete cross tie is the transfer length. Assuring that the transfer length is less than the position of the rail seat is necessary to establish the full pre-stressing force at the load point of the concrete tie. Models have been developed based upon empirical data to predict the transfer length of concrete members given key design parameters. Given the release strength and design geometry of the reinforcement steel, accurate predictions can be made as to what the anticipated transfer length will be. The geometry of the indented profile in pre-stressing steel has been found to be critical for minimizing the fracture propensity of the concrete member and reducing the overall transfer length. Edge wall angles of the reinforcement wire indents have been shown within this study to have a critical influence on the fracture propensity of the concrete medium. Steel produced with too shallow or too steep indent edge wall angles generate excessive internal forces rupturing the concrete. By modeling the behavior of the transfer length in concrete members, the design and production tolerances can be better controlled increasing the life expectancy of concrete ties. This results in decreased costs for the rail infrastructure and greater uptime of tracks utilizing pre-stressed concrete railroad ties. By improving the overall design of concrete members and by improving the quality control tests used during production a longer lasting and lower cost product may be achieved.

The purpose of this paper is to propose new measurement guidelines for pre-stressing steel reinforcement wire indent geometries. The current guidelines for measuring pre-stressing steel reinforcement wire indent geometries are within ASTM A881M-10. These measurement guidelines provide instructions on measuring indent depth, indent side wall angle, and indent orientation. However, since the creation ASTM A881M-10 new measurements have been presented that serve as better predictors of wire performance than the current measurement requirements. The new measure guidelines presented in this research have been shown to have superior correlation to transfer length and the pull out force of pre-stressing steel reinforcement wires used in concrete railroad ties. These measurement guidelines are intended to more completely quantify the surface profile of pre-stressing steel reinforcement wires and do so in a manner that adheres to the geometric dimensioning and tolerancing standards of ASME Y14.5-2009. The measurement guidelines presented in this research use the concept of minimal zone on a variety of different measurements. This includes measurements such as indent volume, indent surface area, and indent edge wall surface area. These new measurements are shown through a variety of statistical models to be strong predictors of transfer length and pull out force for the given reinforcement wire. By presenting these new measurement procedures that define the surface geometry of reinforcement wire indent geometry in greater detail, suppliers can present more complete information of their wire type to consumers. Likewise, consumers will be able to more fully define the design requirements that are needed for their pre-stressed concrete railroad ties. The overall impact of the proposed changes will be the improvement of the quality control of pre-stressing steel reinforcement wires and the extended lifespan and durability of pre-stressed concrete railroad ties.