Browsing by Author "Zarembski, Allan M."
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Item Application of New Lubricant and Modifier Formulations for the Reduction of Wheel Squeal Noise Under Freight and Passenger Service(American Railway Engineering Association, 1999-09) Zarembski, Allan M.; Chiddick, Kelvin S.Wheel sequel noise on curved track is a serious problem in residential areas where the tracks are near or adjacent to homes and residences. This was the case in a Southern California community that was adjacent to a Southern Pacific Railroad mainline that carried both freight and passenger traffic. The specific wheel squeal problem was associated with the negotiation of the moderate curved track by the mix of traffic at a range of speeds and operating conditions. While significant noise levels were recorded by all of the traffic, to include commuter and inter-urban passenger traffic, the highest levels of noise were recorded by intermodal freight equipment, both trailer and container carrying. These n0ise levels were of significant magnitude and resulted in numerous complaints as well a'$ follow up lawsuits from the residents. In order to address this noise problem, the dynamics of the wheel/rail interaction mechanism was examined and a two part solution applied. The solution consisted of using a low coefficient of friction modifiers on the gage face of the high rail of the curve(s) in conjunction with a high positive coefficient of friction modifiers on the top of the rail head on both the high and low rails. In this configuration, lateral slip of the wheel tread across the rail head was significantly reduced, together with the more traditional flanging effects 011 the gage face of the high rail. The result was a significant reduction in the level of noise generated by all of the traffic types. In order to achieve this dual application at specific locations on the rail head, a high rail vehicle mounted application system was developed and utilized. The hi-rail based system allowed for a uniform and accurate application of the friction modifiers onto the rail. However, the friction modifiers deteriorated with time and traffic (as a function of the number of axle passes), and as such had to be reapplied on a regular and ongoing basis. This paper describes the development and application of this combination of friction modifiers to the high noise curve(s) as well as the determination of the rate of degradation of the friction modifiers under traffic. The testing of the Friction Modifiers (Lubricants) performance led to the development of a well defined friction modifier effectiveness degradation curve which served as the basis for an ongoing program of friction modifiers aimed at keeping the level of noise below a defined threshold. In addition, the need for a "reasonably long" interval between friction modifier applications led to the development of an extended life version of the friction modifiers that made them appropriate for use in an ongoing maintenance application.Item BNSF Tests Risk-Based Ultrasonic Detection(Railway Track & Structures Magazine, 2001-02) Palese, J. W.; Zarembski, Allan M.; Patel, P. K.As the railroad industry continues its focus on increased safety, rail defects and resulting rail caused derailments, have become an important area of interest. Analysis of FRA statistics on reportable mainline derailments, attributed to rail defects, shows an overall industry increase in reported derailments per billion gross ton mile (BGTM) of 4% in the period 1997 to 1999 [1,2]. This trend is illustrated in Figure 1 together with the corresponding increase in the average cost of rail related derailments for that same time period of more than 40%. Examining the FRA derailment data further, Figure 2 shows the distribution of derailments by rail defect type along with the average cost of derailment for that defect type. This figure clearly shows that the most predominant cause of rail related derailments is the transverse defect or TD class of defects, with the Detail Fracture (DF) representing the second most common cause of rail related derailments. For the entire range of rail defects, the average derailment cost varied from $200,000 to $1,400,000 depending on defect type, with an overall average of the order of $400,000. Note, this is FRA reportable cost only, the actual cost of the derailment, which could include loss of lading, train delays, or train rerouting, can be double that amount. This increasing trend in rail related derailments suggests that there is a need for improved rail maintenance and/or inspection practices to prevent the occurrence of these defects or to find the defects before they cause these expensive derailments. These improvements can take several forms, to include more aggressive rail replacement or maintenance practices or improved rail testing equipment. However, the focus of this article is on a easier to implement approach, one that can be applied almost immediately with a relatively modest impact on a railroad’s maintenance of way budget, specifically the improvement in the scheduling of conventional rail test equipment. As rail accumulates tonnage, it tends to develop more internal fatigue defects, based on various factors such as metallurgy of the rail, traffic (to include such factors as axle loading and speed), track support conditions, etc. This behavior is illustrated in Figure 3. As defects occur more frequently, it becomes important to test more frequently in order to insure that internal defects can be located and replaced before they have the opportunity to propagate to failure, and possibly result in a derailment. Earlier studies have indicated that approximately 1.3 derailments occur per thousand defects (detected plus service), thus highlighting the importance of matching test frequency to the rate of defect occurrence [3]. Simplistic rail test scheduling approaches, such as those based on annual tonnage levels, which do not account for aging rails and corresponding increased defects, do not give the railroad the flexibility to adjust test frequency to the actual rail conditions encountered. Likewise, simplified “rules of thumb” for scheduling ultrasonic testing, while often accounting for such factors as age of rail (usually in cumulative MGT) annual traffic density, class of track, type of traffic, defect counts, etc., do not do so in a manner that is directly tied into the “risk” of a derailment occurring. Rather, it is necessary to have a risk based scheduling methodology which makes use of site specific and directly measurable performance parameters that, in turn, can be related to a defined level of risk. Such a methodology was developed by US Department of Transportation Center Volpe National Transportation Systems Center [4], and further enhanced by ZETA-TECH Associates, Inc. [5].Item Burlington Northern's Assessment of the Economics of High Capacity/ Heavy Axle Load Cars(American Railway Engineering Association, 1990-05) Zarembski, Allan M.; Newman, R. R.; Resor, R. R.North American freight cars and trains have been growing heavier for many years. For the most part this has been a response to competitive pressures, the inflexible nature of train crew costs, and the changing mix of traffic. The shift in traffic towards bulk commodities and unit trains (grain, coal, ore, and aggregates) was one manifestation of this change in traffic mix and its consequent movement toward heavier cars. Figure I shows graphically the near doubling of average car capacity since 1929. This trend to heavier cars has been accompanied by considerable research into the costs and benefits of larger cars and heavier trains. In particular, the issue of increasing car size, and consequently increasing axle loads, has been the subject of much examination and discussion. There s also the related issue of increasing the loading of existing cars. This issue was raised in 1986 at the Third International Heavy Haul Railways Conference (I) attended by representatives of Burlington Northern's Research & Development Department. In the opening paper of the conference, representatives of Mt. Newman Mining Co. and BHP Melbourne Research Laboratories stated that heavier axle loads were not only technically feasible but were also economically feasible under the conditions as experienced, tested, and applied in Australian heavy haul operations. This paper emphasized that since existing ore cars were only loaded to about 75% capacity, axle loads could be further increased. Following the First International Heavy Haul Railways Conference in 1978, axle loads were increased by the Australians to 33 tonnes (36.3 tons) and this axle load was adopted as a system wide standard. The successful gain led to adoption of an additional axle load increase to 35 tonnes (38.5 tons). Even higher axle loads appeared economically justifiable; however, the 35 tonnes provided an additional margin of comfort below the 37 tonnes (40.7 tons) level at which the Australian road's studies indicated that major, cost-impacting bridge upgradings would be required. As illustrated in Figure 2, the main point of the Australian findings was that axle loads between 33 and 37 tonnes (36 and 41 tons) were expected to reduce total railway maintenance and replacement costs. Costs were reduced 1-4% by increasing axle loads from 36 to 40 tons but began increasing beyond that point. In many ways, BN's Northern Coal Route is similar to the Mt. Newman Railway. It is composed almost entirely of welded rail, the bulk of it being 132 1b. section. Locomotive-borne lubrication is used and profile grinding of the rail is carried out twice per year. The vast majority of the traffic on the line is unit coal traffic. However, since BN's Northern Coal route is not an isolated captive railway, maintenance standards for both track and structures may be less rigorous. Mixed traffic and bridges of varying age and capacity present problems not encountered by the Australian railways.Item Computerized Maintenance Planning and Reporting Systems(1995-06) Zarembski, Allan M.Item Concrete vs. Wood Ties: Making the Economic Choice(1993-10) Zarembski, Allan M.Track components must satisfy two basic criteria for acceptance. The first criterion is a performance criterion, which addresses whether the component has sufficient "strength" to function and survive in the railway environment. The second criterion in the economic one, whether the cost of the component is economic with respect to other similar components or products. This second criterion comes into play only if the first is satisfied, i.e., the component or system must have adequate performance, before its relative economics is even considered. Only when that performance criterion is met, the economic criterion comes into play. One clear application of this approach is that of the cross- ties and fastener systems, specifically that of the concrete cross-tie as compared to the traditional wood cross-tie that has been used by railroads for over two hundred years. While concrete tie designs have been around for many years, it has only been in the last two decades that their performance has been deemed to be adequate to withstand the severe loading environment of North American freight operations. Once this performance criterion has been satisfied, i.e., once it has been established that the concrete cross-ties can function and survive in the heavy haul environment, then the economics of this alternate tie system enters into the consideration of railway engineers. Specifically, the relative economics or the concrete tie system must be compared with the existing conventional systems, wood ties with cut spikes. In addition, the relative economic of these systems would have to be compared with several other technically proven systems, such as wood ties with alternate (elastic) fastening systems. This economic comparison, however, is not a simple matter. Because different tie/fastener systems exhibit different lives, require different maintenance activities, and affect other maintenance activities differently, simple comparison of the initial or "first" cost is not adequate. Rather, a comprehensive comparison of the costs and benefits of the alternate systems over their entire service lives is required, i.e., a "life cycle" cost analysis. This is further complicated by the fact that component lives and behavior vary significantly as a function of track and traffic characteristics, as well as individual railroad practices. Thus, the relative economics of these alternate cross-tie systems is not fixed, but vary with many of the operating and maintenance parameters. One approach that has been effectively used to address these significant differences is the development of life cycle costing computer models that can be run on personal computers. This approach led to several such models, such as the SelecTie model developed by ZETA-TECH Associates, Inc. for the Railway Tie Association. Such a model is capable of incorporating a comprehensive analytical methodology and allow for the ready (and rapid) changing of key parameters and the "instantaneous" recalculation of the results. This approach has been found to ZETA-TECH Associates, Inc. 2 1993 be an effective means of carrying out economic benefit comparisons, particularly ~such life cycle benefit analyses. The basic analytical approach used in this methodology (and in the model itself) is a present worth analysis approach, in which all the costs associated with the two alternative systems are examined and compared in terms of a "present worth". Thus, any future costs or savings associated with the two systems are brought to the present, and the "worth" of these future costs calculated using an appropriate interest rate. (Thus, taking into account the time value of money.)Item Controlling Rail and Wheel Wear on Commuter Operations(American Railway Engineering Association, 1993-10) Bohara, A. P.; Zarembski, Allan M.The Regional Railroad Division of the Southeastern Pennsylvania Transportation Authority (SEPTA) operates approximately 450 route miles of commuter operation in the Philadelphia metropolitan area. In 1991, the railroad division began experiencing an unusually high rate of wheel and rail wear, particularly on sharp curves on the commuter rail lines. This wear was predominately wheel flange/rail gage face wear with an apparent correlation between the increase in wear on both the wheels and the rails. The cause of the increase in wear was not clear or well defined, and as a result the most appropriate form(s) of corrective action was difficult to determine. In order to effectively address this issue, a comprehensive examination of the wear mechanisms, wheel and rail, was undertaken, together with a de- tailed study of the dynamic interaction between the wheel and the rail. As part of this detailed study, a series of specific activity areas were defined, and each of these areas were ad- dressed both individually and as part of the overall integrated study. These specific study areas included the following: 1. Field investigation of rail and wheel wear. 2.Computer simulation of wheel/rail interaction and wear, 3.Analysis of wheel and rail profiles. 4.Analysis of rail grinding effects and requirements. 5.Evaluation of rail lubrication effectiveness. 6.Evaluation of track geometry (super-elevation and unbalance) effects. 7.Assessment of critical measurements and tolerances. 8.Economic benefit analysis. This paper presents a summary of each of these activities together with some of the overall finding and recommendations of this study. It should be noted here that this study was specific to the conditions and operations of the Railroad Division of SEPTA, and any extrapolation of these results to other properties should be done with extreme caution.Item Controlling Track Forces during Introduction of New High Speed Trains(International Railway Journal, 2001-10) Zarembski, Allan M.; Palese, J. W.; Bell, J. G.As part of its program to introduce a new generation of high speed trains in the United States, Amtrak, the owner of both the equipment and the infrastructure, defined an objective of minimizing any increase in track maintenance or damage to the track structure or its components. The concrete ties on the Northeast Corridor were a particular source of concern in light of the tie cracking problems that had been experienced by Amtrak in the 1980s. The primary focus of attention was the dynamic wheel/rail impact forces applied to the track structure. Research studies have shown that significant increases in wheel/rail dynamic forces can occur at high speeds with a corresponding potential increase in track degradation, component failure, and track maintenance costs. To avoid this effect, Amtrak introduced a specific requirement for the design of the new high speed Northeast Corridor equipment to maintain the level of dynamic vertical wheel/rail forces applied to the track no higher than current levels. Thus for proposed new electric equipment to be operated at 150 mph, the dynamic impact forces were set at a level corresponding to the existing AEM7 electric locomotive operating at 125 mph. Likewise for the proposed new fossil fuel (diesel) equipment to be operated at 125 mph, the force levels were set to that of the existing F40 diesel locomotive operating at 90 mph.Item Corrugation Behavior in the Freight Railroad Environment(American Railway Engineering Association, 1987-10) Zarembski, Allan M.; Izbinsky, G.; Handal, S. N.; Worthington, W. M.Rail corrugations are a phenomenon found on almost all types of railway systems throughout the world. Corrugations have been defined to be “rail head anomalies that appear on the surface of the rail in a repeatable manner along the length of the rail” (1). Though they appear as "waves" or regularly spaced discontinuities on the railhead, they are not always uniformly spaced, but tend to vary about an average (or, as shall be seen later in this paper, average range of) wavelength(s) (Figure 1). Corrugations are generally classed according to their range of wavelengths, which is the peak to peak (or valley to valley) distance between adjacent corrugations, as illustrated in Figure 1. The corresponding depth of the corrugation is the difference in height between the peak and valley of the wave. Corrugations can range in depth from .005 inch (where they are barely detectable) to .050 inch and greater (where there is no doubt whatsoever as to their presence), depending on the corrugation type and wavelength. Consequently, they can result in significant dynamic forces being applied to the rail and the rest of the track structure, as vehicular traffic moves over the site of the corrugations. However, in studying the phenomenon of corrugations it appears that rather than having simply one type of corrugations, there is a broad range of corrugations that vary in characteristics (depth and wavelength) with different conditions. This is particularly true in examining the differences in corrugations observed on heavy axle load freight railways, such as the North American freight railroads, and lighter axle load passenger and transit railways. Several authors (2,3) have suggested at least three types of corrugations corresponding to three different sets of railway conditions and operations. The first class is the very short wavelength class of corrugations, referred to as either "roaring rail (2) or "corrugations" (3), associated with light axle load passenger and transit (4) systems. These corrugations range in wavelength from 1 to 3 or 4 inches. The second class of corrugations is the "freight railroad" corrugations, most frequently associated with heavy axle freight operations. These have been referred to as "short wave corrugations" (2) or simply "short waves" (3) and have traditionally been associated with wavelengths of between 4 and 12 inches. However, as will be seen in this paper, the actual range of these corrugations is between 6 and 48 inches. The third class or corrugations, generally referred to as “long waves”, are associated with high speed types of operations. The actual range of characteristics of these wavelengths have been the subject of some debate (5), however, they have been associated with wavelength of 50inches and greater (3). In view or the significant differences in definition of the different classes of corrugations, and the need for a suitable identification of the type of corrugations found in the North American freight railroads, it was determined that a detailed examination of the characteristics of these freight railroad corrugations was required This paper presents the results of this examination of the characteristics or North American freight railroad corrugations. As noted above, this study addressed the wavelength band of corrugations most frequently found on the North American freight railroads. Specifically, this report will examine the general distribution of corrugation, both by wavelength, and by depths. The relationships between corrugations; found on five different freight railroads, the influence of track structure (wood ties vs. concrete) on the corrugations, and the effect of rail grinding on corrugation removal. In addition, it attempts to address the issue of the consequences of corrugation. i.e. the effect of corrugations on wheel rail dynamics. It must be noted here, that while these results represent a significant amount of effort, both in the collection of a large amount of data from five different railroads, and in the analysis of this data, the results presented in this paper represent the preliminary results of this study.Item Design Considerations in Stiff Track Modulus Environments(Railway Track & Structures Magazine, 2002-02) Zarembski, Allan M.; Redden, J. W. P.; Selig, E. T.The Alameda Corridor is a 20-mile long rail corridor that will provide improved freight access for the Union Pacific Railroad and the BNSF Railway from the Ports of Los Angeles and Long Beach to the rail yards and points east. The Mid-Corridor Trench is a 10-mile long section of the Corridor that will grade-separate the rail line from vehicular traffic via 30 new overhead bridges. The Trench is open topped, 30-feet deep and 51-feet wide. Initially it will have two main tracks although it was designed for a future third track. The general configuration of the Trench consists of three-foot diameter cast-in-drilled hole (CIDH) piles placed four feet on center. Connecting components are the shotcrete facing, cast-in-place concrete floor slab, integral top wales and precast concrete struts. See Figure A. The tracks will have 136-lb. continuous welded rail with concrete ties. The cast-in-place concrete floor slab varies in thickness from 48 inches to 12 inches depending on the water table and soil conditions. Originally, twelve inches of ballast was planned between the concrete floor and the concrete ties. Analysis of this design showed this to be a very stiff, non-resilient track modulus environment. The initial concern was the effect the train loads would have upon the ballast in terms of accelerated degradation. However, other components of the track structure, specifically the concrete ties, rail fasteners, rail pads and the rail itself were also identified as having the potential for reduced service life and higher levels of maintenance.Item Determination of Track Gage Widening Parameters(American Railway Engineering Association, 1981-05) Zarembski, Allan M.; Bhateja, RajivGage widening is a serious railroad track problem related to the condition of the ties and fasteners. Recently, an improved analytical model for track gage widening was developed. This model predicts the response of the rail to applied external loading and the results agree well with laboratory and field test data. This paper summarizes this improved analytical model and presents a numerical computation technique for the determination of the fastener stiffness parameters. This technique, which utilizes static load-deflection test data, permits a closer correlation between the test and analytical results. A set of fastener stiffness parameters for conventional U.S. track is also presented.Item Determining the Cost of Track Maintenance(Railway Track and Structures, 1993-04) Zarembski, Allan M.A proper understanding of the costs of doing business is essential in any business environment. In the transportation industry generally, and in the railroad industry in particular, this understanding can be difficult to achieve. Railroads carry many different commodities, moving in a variety of cars of different sizes and weights and in trains of varying length, motive power assignments, and maximum operating speeds. The effect on costs of an incremental change in train length, for example, or car weight, can be difficult to predict. While railway costs in general are difficult to predict, maintenance of way costs, and specifically the relationship between maintenance of way costs and critical traffic and right of way parameters, are especially difficult to accurately quantify. This has always been a problem in track maintenance planning accurately determining the rate of failure of track components and, more to the point, accurately determining the cost of maintaining the track structure. These difficulties are due to many factors, not the least of which being the complex relationships between component life or "damage" and external loading and environmental factors. Recent research has shown that many of these relationships are non-linear, such as the non-linear damage effects caused by differing axle loads of various traffics. These non-linear damage effects, in turn, translate into non-linear cost sensitivities. Further compounding the difficulty in defining track maintenance costs are the conflicting trade-offs that are inherent in high density tracks. While high densities may allow for some economies of scale in maintenance of way practices, they also limit maintenance access, which in turn drives up costs. Furthermore, the level of traffic density has a major impact on costs. On lightly used rail lines, increases in traffic can be accommodated with only small increases in the cost of track maintenance. But as traffic continues to increase, the environmental mechanisms that limit track component life when no traffic uses a track (rust and decay) become insignificant on heavily trafficked railroads. Rust and decay are replaced by abrasive wear and crushing; rails and ties do not remain in track long enough for environmental mechanisms to dominate life. Several of the "traditional" railway costing methodologies rely heavily on an economy of density effect, generally in the form of a simple, statistically derived relationship between cost and such gross density parameters as ton-miles or train-miles. Such regression analyses are the traditional and accepted methods for railroad costing, particularly regulatory costing for the Interstate Commerce Commission (ICC) or other regulatory agencies. However, these assumptions can lead to a misspecification of incremental track maintenance costs as traffic density increases. They can further result in an improper allocation of budgetary resources for track maintenance, particularly on the highest density routes which are generally the most sensitive to the level of maintenance and condition of the track. Therefore, it is important to both maintenance of way officers and to senior railroad management that accurate track maintenance costs be obtained and used in the planning and budgeting process. In recent years, research into the mechanisms governing track degradation has indicated that train miles or ton miles are not necessarily adequate as model variables with which changes in costs can be associated. The speed of operation, axle load of the equipment, and key characteristics of the track and traffic are all important determinants of track maintenance costs. The growing understanding of the factors governing track component life has led to the development of much more complex models. Cost models in common use today rely on one of two basic approaches: •Engineering Cost Models •Allocation Models The engineering models are deterministic in nature, relying upon mathematical models of physical deterioration to predict the required quantities of track maintenance, and the application of unit costs to determine total required expenditures. Allocation models, such as regression equations developed from industry wide cross-sectional data, address the allocation of costs between different traffic types on a given railroad or on a given route.Item Development and Implementation of Integrated Maintenance Planning Systems(Transportation Research Board, 1998-01) Zarembski, Allan M.Railway engineering departments have focused attention on improving the efficiency of their maintenance operations through the use of a range of computerized inspection, analysis, and planning tools. These tools are designed to help identify where resources are really required and schedule the necessary maintenance operations. These tools include; automated inspection systems, user friendly databases, and maintenance planning software systems. These tools have been applied to date in the areas of rail maintenance (the highest track maintenance cost category), surfacing (ballast/track geometry maintenance), and to a lesser extent, tie maintenance. In the case of the first two, rails and surfacing, high speed automated inspection systems are available which provide the ongoing input into the condition of the track and its day to day changes. In the case of ties, new generation track strength measurement vehicles are currently being introduced, to provide information data on the condition of the tie and fasteners. This inspection data, together with track component, traffic, and geometry information, is stored in an integrated database and then fed into the analysis and forecasting element of the integrated maintenance planning system. This is the element that takes this data and analyzes it, to predict where and when components will reach their failure limit and require replacement. This element makes use of fundamental engineering behavior relationships, in the form of track degradation models, to predict component life, identify time and location of component replacement, and combine this information into an integrated maintenance plan. This paper describes the steps involved in developing such an integrated maintenance planning system and cites examples, particularly in the case of rail, to show how these systems have been developed and implemented on several major rail systems.Item Development of an Improved Vehicular Loading Characterization Associated with the Gage Strength of Track(American Railway Engineering Association, 1982-01) Manos, W. P.; Scott, J. F.; Choros, J.; Zarembski, Allan M.This report describes the development and application of a simplified technique for presenting vehicular loading information in a consistent and uniform manner. The load data, both lateral (L) and vertical (V), is used to develop a "loading severity", value (5), with which the level of loading can be equated with the associated level of damage to the track, as defined by a given rail head deflection. Specifically, it addresses the gage retaining strength of the track structure, in general, and the tie-fastener-rail system, in particular. This is done by means of a linear relationship S=L–μV where μ is the effective friction coefficient between the rail and the tie. Data were taken from five sets of fie1d and laboratory tests of track gage widening, used to validate this relationship and to determine the effective friction coefficient for conventional track. The linear relationship between lateral (L) and vertical (V) loads indicates that the equation shown above is a good approximation to the equivalent levels of loading. Examination of the test data and analysis of the effective friction for the numerous individual tests in the five series shows a normal effective friction distribution, with a mean value of 0.4 and a standard deviation of 0.1.Item Development of Rail Gage Face Angle Standards to Prevent Wheel Climb Derailments(American Railway Engineering Association, 1996-03) Zarembski, Allan M.Rail represents that part of the track structure that first "meets" the wheel and thus directly carries the wheel/rail loading imposed by the traffic operating over that track. As such it is subject to a significant level of dynamic loading; vertical, lateral, and longitudinal, and it must support these loads safely and economically. This requires an adequate level of strength of the rail, together with a proper support capability of the wheels. Traditional rail standards, and in particular rail wear standards, are generally strength based, so as to insure that the rail can adequately support this traffic without failure, e.g. fracture under traffic. By combining strength based wear standards with ongoing monitoring of fatigue failures (fatigue standards), railway maintenance officers define a zone of safety for the rail, beyond which the rail must be removed from track. In addition, rail represents a major cost area in the maintenance of the track structure, representing, for main line freight railroads, as much as 50% of the total variable cost of track maintenance. Thus, the decision as to when and where to replace the rail is an important one, not only from the point of view of safety, but also from the point of view of cost and economics. Leaving rail in track for too long can result in a service failure and the potential for a derailment. Removing a rail prematurely translates into significant costs for the railway. Thus maintenance officers must maintain a proper balance between safety and cost control. In the case of rail, this is done through the use of cost effective standards for the rail that maintains an adequate margin of safety for the track structure. To add to the complexity of maintaining these adequate standards, evolving operating conditions and maintenance practices have resulted in significant changes in the way railways determine when rail should be replaced in track. These changes stem directly from changes in maintenance of way practices and materials that have occurred during the past two decades, i.e. better higher strength rail, cleaner steel, improved lubrication and grinding practices, etc. as well as from changes in operating practices, i.e. heavier trains, increased axle loads, higher operating speeds, etc. The net result of these changing practices has been the extension of the service life of the rail, and often an overall reduction in rail maintenance costs over that life [1]. Thus, for example, the decreasing importance of rail joints, and the dramatic extensions of rail life through the use of effective lubrication, grinding, and improved steels [2]. While increasing axle loads have resulted in an increased emphasis of fatigue defects, rail wear remains a key replacement criterion for all rail systems to include freight, passenger, and transit systems. Thus, the importance of maintaining appropriate and adequate rail wear standards likewise remains. Recently, increased attention has been paid to the wheel/rail dynamic environment of the track structure, with major emphasis placed on the shape of the wheel and the rail [3]. This has led to a better understanding of several classes of derailments, to include those wheel climb derailments associated with excessive wear of the rail and/or the wheel [4]. This has become of even greater importance in recent years, as several classes of derailments have been associated with these levels of wear. It is the focus of this paper to examine those conditions, and to identify those rail wear criterion and standards that can reduce the potential for occurrence of these classes of wheel climb derailments.Item Dynamic Rail Overturning: Modelling and Application(1979-09) Torkamani, M. A. M.; Bhatti, M. H.; Zarembski, Allan M.The problem of rail overturning, which constitutes one of the many causes of derailments, is of growing concern to the railroad industry. A better understanding of the rail overturning mechanism can prove to be an important step towards the development of safe and adequate railroad track systems. An analytical model for examining the dynamic behavior of rail overturning is developed in Ref. [1]. The mathematical model of the rail track system and dynamic equilibrium utilized to determine the lateral deflection and rotation of the rail subjected to time-dependent lateral and vertical forces and constant axial force. The analysis is based on linear elastic theory.Item The Economics of Rail Grinding and Rail Surface Maintenance(American Railway Engineering Association, 1986-10) Zarembski, Allan M.This paper develops methodologies for the economic analysis of the benefits (and costs) of rail maintenance techniques such as rail grinding, both conventional and profile grinding, and rail surface welding. As such, it examines the effect of rail surface conditions on component life, such as rail life, and applies the results to the economic analysis of representative railroad scenarios. The results of these analyses indicate that significant economic benefit is derived from proper maintenance of the rail surface condition, This appears to hold true in the case of rail surface fatigue on the l1igh rail of lubricated curves, and in the case of rail corrugations on the low rail of unlubricated curves. finally, it is shown in this analysis that frequent rail grinding, such as when the level of corrugations is relatively small, can reduce the overall cost of rail grinding.Item Effect of Increasing Axle Loads on Rail Fatigue Life(American Railway Engineering Association, 1982) Zarembski, Allan M.This report presents the results of an investigation into the effects of increasing axle loads on the fatigue life of tangent, continuous welded rail (CWR). Two independent studies were conducted. The first utilized a statistical analysis technique, which obtained probability distribution curves for rail defect data. The second utilized a fatigue analysis methodology for the prediction of rail service life. Both techniques have shown good correlation between calculated results and service experience. For the first study, rail defect data was obtained from two mining railroads: one operating 100-ton car unit trains; the other 70-ton car unit trains. These were then compared with data from both a "typical" mixed freight traffic railroad and from FAST (l00-ton cars). For the second study, a rail fatigue life model was used to calculate the rail life under loadings that were representative of the same three types of operations. The results of both analyses show that increasing the axle loadings results in increased rail defect occurrences, with a corresponding decrease in rail fatigue life for tangent CWR. This reduction is by about 40% of the life of the rail, in million gross tons (MGT), when the loading is increased from 70-ton car (200,000 lb.)** to 100-ton car (236:000 lb.) loading conditions. This effect, which is seen for both heavy (132 lb.) and medium (119 lb.) rail sections is quite significant, and must be taken into account in any future studies and economic analysis.Item Effect of Increasing Axle Loads on Rail Fatigue Life(British Rail Research ( Part of the Old British Rails), 1983) Zarembski, Allan M.; Stone, D. H.; Wells, T. R.; Armstrong, R. A.This report presents an investigation into the effects of increasing axle loads on the fatigue life of tangent, continuous welded rail (CWR). Two independent studies were conducted. The first utilized a statistical analysis technique, which obtained probability distribution curves for rail defect data. The second utilized a fatigue analysis methodology for the prediction of rail service life. Both techniques have shown good correlations between calculated results and service experience. The results of both analyses show that increasing the axle load results in an increased incidence of rail defect occurrences, with a corresponding decrease in rail fatigue life for tangent CWR. This reduction is by about 40% of the life of the rail, in million gross tons (MGT), when the loading is increased from 70-ton cars (200,000 lb.) to 100-ton cars (263,000 lb.). This effect, which is seen for both heavy (132 lb.) and medium (119 lb) rail sections, is quite significant, and must be taken into account in future studies and economic analyses.Item Effect of Rail Section and Traffic on Rail Fatigue Life(American Railway Engineering Association, 1979-03) Zarembski, Allan M.The current trend towards increasing traffic and wheel loads has focused industry attention on maintenance of the track structure. In particular, the problem of rail failure and replacement has emerged as a key issue in the track maintenance, safety, and economics arenas. The ability to reliably predict rail service life for different traffic and track conditions is of paramount importance in examining and developing suitable maintenance procedures. Furthermore, the proper matching of rail section size with traffic and track conditions is essential for any cost effective maintenance program. Traditionally, the dominant criterion for the replacement of rail in mainline track has been either rail end batter or rail head wear. Increasing use of continuously welded rail has significantly decreased the occurrence of rail head batter. Thus rail head wear remained as the dominant rail replacement criterion. However, with the increasing traffic loads, particularly the increasing wheel loads, that the track structure is being called upon to support, the development of fatigue "defects" in the rail is emerging as a major replacement criterion for mainline tangent track. In fact, current and proposed safety criteria now emphasize the detection of fatigue defects as they develop in tangent track. Thus, it appears that in many instances, fatigue, rather than wear, is the replacement criterion for rail in service. Recent development of a fatigue analysis methodology for prediction of rail service life in mainline tangent track was reported in References (1) and (2). This methodology utilizes a characterization of the service load environment together with rail material fatigue properties to calculate the service life of the rail. Reference (2) presented the complete analysis methodology and compared the calculated results with data obtained from service experience. The correlation was quite good. The objective of this paper is to extend the results presented previously to study the effect of changing the rail section size on the rail service life. Additionally, the effect of different traffic loadings, specifically mixed freight vs. unit train traffic, and the effect of varying track support conditions will be investigated.Item An Estimation of the Investment in Track and Structures Needed to Handle 286,000 lb. Rail Cars on Short Line Railroads(Transportation Research Board, 2000) Zarembski, Allan M.; Resor, R. R.; Patel, P. K.Ownership of the U.S. rail industry is divided between eight Class I rail-roads (those with more than $258.5 million in annual revenue) and about 550 regional and short-line railroads. The eight large railroads own about 70 percent of the 273 700 track-km (170,000 track-mi) and account for about 90 percent of industry revenues. The remaining 30 percent of track kilometers belongs to the regional and short-line railroads, which must operate and maintain them with 10 percent of industry revenues. U.S. railroads function as an integrated network; freight originating on a short-line railroad can be delivered anywhere in the United States, Canada, or Mexico. Equipment is freely inter-changed, so the small railroads must handle the same heavy cars as the Class I railroads even though maximum freight car weights have increased in recent years, with cars of 129 844 kg (286,000 lb) becoming common. Many of the smaller railroads own trackage that had been branch lines belonging to the larger companies, and track components and condition are often marginal or inadequate to handle the heavier loads. Yet, if short lines cannot handle heavier cars, they face a loss of revenue and ultimately business failure. ZETA-TECH conducted a survey of short-line and regional railroads to determine the quantities of track materials, bridge repairs, and replacements needed to handle heavier cars. Using standard railroad industry unit costs, ZETA-TECH estimated the cost of this work at $6.86 billion in 1999 dollars.
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