Allan Zarembski

University of Delaware | UDel UD · Department of Civil and Environmental Engineering

Cross-ties represent a key infrastructure asset of the railroad industry. Recent research has shown that the cross-tie life is not only affected by the traditionally defined load and track design parameters but also by support condition, and in particular, support condition as represented by the condition of adjacent cross-ties. This paper builds u...

Transportation corridors constructed using through- and side-cuts are susceptible to hazardous slope failures, potentially causing infrastructure damage, operational suspensions and loss of life. To monitor the stability of known geohazards at the local scale, geotechnical investigation of each slope is typically performed to calculate a factor of...

Crossties failure and deterioration can cause major safety issues, including loss of gauge and ability to properly support the rail. Thus, understanding tie degradation behavior is of key importance. Studies have been conducted to assess the degradation behavior of crossties addressing different parameters such as traffic/tonnage, weather and clima...

A Correction to this paper has been published: https://doi.org/10.1007/s40515-021-00182-7

Railroad crossties (sleepers) are a key component of the track structure and play an important role in the support of the track structure and the distribution of train loading through the track. The condition of the crossties has been traditionally monitored by visual inspection, which has, in recent years, been supplemented with automated crosstie...

Sidehill and through cuts are often used in the construction of new rail systems to reduce the length, curvature, and grade of the route to increase operation efficiency. Consequently, rights-of-way that utilize cuts are susceptible to damage from slope failure events such as shallow-rapid landslides and rock-falls. At-risk slopes, or geohazards, a...

The ability to predict track geometry degradation is of critical importance in planning of track maintenance operations. This paper presents results of an FRA sponsored study on the relationship between track geometry degradation and ballast condition as measured by Ground Penetrating Radar (GPR). The study examined six different sites on a major C...

Railroad track substructure condition has historically been difficult to monitor since the substructure is not visible without displacing ballast, making it challenging for engineers to observe degradation and to optimally schedule maintenance. Many methods to accurately classify track substructure condition require invasive measurement techniques...

The railroad industry has historically used the 2-Parameter Weibull equation to determine the rate of rail fatigue defect occurrences and to forecast the fatigue life of railroad rail. However, the 2-Parameter Weibull equation has significant limitations to include inability to analyze segments of track with limited number of rail defects. These li...

This research studies the development of lateral thermal expansion forces on a curved railway track. The geometric alignment of a railway right of way often requires railway tracks to be curved. This curvature which is usually defined by the radius of curvature or degree of curvature represents a higher level of complexity in the track’s analysis a...

Rail transportation plays a vital role in U.S. transportation. According to the National Transportation Statistics report from the Bureau of Transportation Statistics, railroads generate 29% of ton-miles of freight, whereas air, truck, water, and pipeline transportation represent the rest of the freight traffic. In the passenger spectrum, the 2016...

This paper presents an analysis of a new railroad track design based on substructure containing a double layer of geocells plus an additional geogrid layer for application on a new rail line being constructed. This new line is designed to accommodate both passenger and freight operations. The analysis looked at the applicability of the proposed des...

Rail geometry defects constitute a major cause of accidents in the United States. Geometry related accidents are often very severe and damaging. While rail geometry-caused derailments continue to rise according to Federal Railroad Administration (FRA) data, track quality analysis remain effectively unchanged. The use of TQI or track quality index t...

This paper presents a new and useful approach to incorporating Ground Penetrating Radar (GPR) data into track maintenance planning and management. The methodology used herein was a Data Analytics approach examining multiple track geometry runs and GPR data for a section of high speed track on Amtrak's Northeast Corridor. The data included ballast f...

This paper presents the results of a statistical correlation analysis between the occurrence of track geometry defects and tie condition as measured by an automated tie inspection system on a major US Class 1 railroad. This activity focuses on tie condition, as defined by the automated tie inspection system and calibrated to railroad standards, its...

Railroads have long used track inspection vehicles that capture data on a defined interval as the vehicle travels longitudinally down the track. These data can be captured on a constant interval, near-constant interval, or temporally. The data are normally evaluated in real time against exception thresholds, which define locations of safety or main...

As transit vehicle wheels accrue mileage, they experience flange and tread wear based on the contact between the railhead and wheel-running surface. When wheels wear excessively, the likelihood of accidents and derailments increases. Thus, regular maintenance is performed on the wheels, until they require replacement. One common maintenance practic...

Recent research has shown a relationship between track geometry defects and track subsurface conditions as measured by Ground Penetrating Radar (GPR). This paper presents the results of a comprehensive study looking at the development of a probabilitic model for the prediction of track geometry defects as a function of key subgrade parameters as me...

This paper presents results of an FRA sponsored study on the relationship between track geometry defects and track subsurface conditions as measured by Ground Penetrating Radar. The analysis made use of multiple track geometry runs and the associated track geometry degradation behavior combined with Ground Penetrating Radar (GPR) data to include Ba...

Ballast fouling and associated degradation of track geometry is a serious problem for railway systems in general and high-speed passenger rail systems in particular. This paper presents the results of a field test on Amtrak’s Northeast Corridor where a long-term problem area existed near Oakington Road, Havre de Grace, Maryland, near MP 63.7 betwee...

Agencies with safety oversight responsibilities of railroad tracks often perform walking audit inspections of tracks (also referred to as quality audits) to complement and oversee the regular inspections performed by the railway operator or maintenance manager. Traditionally, these audit inspections are scheduled based on the qualitative evaluation...

This paper introduces the application of a data science algorithm in analyzing Big Data related to the volume of missing ballast in a track section and the development of track geometry defects. The data intensive algorithms are necessary in order to effectively analyze over 100,000 segments of track representing nearly 1000 miles (1700 km) of data...

The support structure beneath railroad tracks may appear to be a simple layering of various materials, but rather, it is a complex system working together to distribute the load of passing trains. It is paramount that this structure maintain its designed support properties not only to preserve component life expectancy but to maintain the safety of...

This paper presents an application of multivariate regression splines (MARS) to a model looking at the railroad track defect behavior. MARS is a non-parametric function estimation technique that shows great promise for fitting non-linear multivariate functions. The MARS approach was used here, together with traditional regression analysis technique...

Paper presents results of FRA sponsored study on relationship between geometry defects and rail defects and specifically the relationship between presence of one of more track geometry defects and development of rail defects at that same location. In this study, approximately 335,000 track geometry defects were correlated with approximately 26,000...

High-density railway lines experience a high rate of deterioration on the running surface of the rails; it can be addressed by rail grinding in order to reduce the frequency of rail replacement. Rail grinding includes additional complex features beyond what is usually considered in conventional grinding. Although extensive empirical experience exis...

This paper presents the results of a study on the relationship between missing ballast and the development of track geometry defects. More specifically, this paper looks at the relationship between missing crib and shoulder ballast, as identified by automated ballast profile measurement systems, and the development of ballast related track geometry...

Use of Switch Profile Data for Enhanced Analysis of Wheel Rail Behavior at Switch Point

Railway is an environmental friendly method which has been widely used in the land transportation driven by electric powers, without harmful emissions and unhoped traffic jams. And it is important to guarantee the running safety through the technology of rail grinding. However, the empirical processes have limitations on the expanded requirements o...

Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding tech...

The railroad track substructure and specifically its ballast and sub-ballast layers play a key role in the maintenance of the stability and geometry of the track structure. However, because it traditionally has not been readily accessible below the surface of the ballast, very limited information about its conditions was available, without extensiv...

Rail grinding continues to be one of the most effective techniques for extending rail life, improving wheel/rail contact behavior, and reducing the overall cost of track maintenance. While the ability to more effectively implement improved rail grinding programs continues to expand, the understanding of the grinding mechanism itself has not kept pa...

A method of inspecting a turnout of a track includes the steps of: capturing images of the components of the turnout; converting each image into a set of coordinates that traces the transverse cross-section of a rail profile; analyzing the rail profile to determine if the rail profile is a profile of arunning rail portion or a component. Upon deter...

The turnout represents a complex component of the track structure that generates high levels of vertical and lateral dynamic forces. This in turn results in high levels of wheel/rail contact stress and corresponding high rates of track degradation, significantly greater than in conventional track. Furthermore, the location of these high contact str...

What are some of the practical obstacles to a “shared interests” between a freight railway business and the proposed new higher speed passenger entity? This paper discusses the real “tension” between the two business interests that fund freight trains versus those that support and fund higher speed passenger trains as they attempt to share the same...

As track geometry degrades, and in particular as track surface and cross-level (as defined by a Track Quality Index or TQI) degrades, railway vehicles going over that degraded track experience increased vertical dynamic behavior and increased vehicle/track interaction. This in turn translates into increased wheel/rail dynamic forces as well as incr...

In order to reduce the cost of new intercity passenger rail corridors, the operation of higher speed passenger networks on existing freight corridors is being examined and considered. The issues to be addressed in such operations include the one-time upgrade of the track to allow for this higher speed passenger traffic and the ongoing maintenance c...

The issue of broken rail risk has been of major concern to railways worldwide, to include passenger and freight railways. Broken rail derailments on high speed passenger operations are of particular concern, as depicted by the consequences of the 2000 Hatfield derailment in the UK. Research studies have shown that the risk of broken rail derailment...

This paper discusses a new tool designed to assist in the performance of switch and crossing inspections. Known as Switchlnspect^TM, this PDA-based program allows the inspection to be conducted in electronic format. With measurements and defects recorded in this manner, the collected information may be used to more efficiently manage main...

A new generation of track safety management tools has been developed to quantify and analyze the risk associated with key track failure modes. These risk-based assessment tools have been shown to contribute directly to a reduction in track failures through their ability to selectively identify high-risk locations and bring remedial action to bear o...

The innovations in hand-held computers and the replacement of traditional paper based recording of track inspections with a digital based approach, are discussed. The latest generation of Personal Digital Assistants (PDAs) are capable of functioning in severe weather and environmental conditions. The range of capabilities, to include extensive data...

Railroad turnouts are discontinuities in the track structure that are needed to move a rail vehicle from one track to another. These discontinuities generate high dynamic forces, to include high lateral forces into and through the switch, due to abrupt or non-uniform changes in track geometry. In the diverging route, these discontinuities frequentl...

Risk management and together with its associated management of safety is a fundamental focus of railway officers worldwide. This includes the issue of derailment prevention as well as the related issue of risk management for those categories of track failure or degradation that can result in a derailment. Recently, a new generation of track safety...

The use of grinding quality index (GQI) in assessing the effectiveness of rail grinding , as well as in the planning and prioritization of rail grinding activities is discussed. The GQI are determined through comparison of the measured rail grinding profile with the desired (target) rail profile. The GQI is designed to serve as a quality control me...

Recently, there has been a movement in the railroad industry to begin assessing track geometry and track safety on the basis of real-time predictions of rail vehicle behavior in response to track geometry measurements while on board a track geometry car running at full track speed. With support from the Federal Railroad Administration, ZETA-TECH As...

The development of methodology for identification of high-risk track-buckling sites by ZETA-TECH Associates and BNSF is discussed. Track-buckling, the sudden lateral movement of the track due to thermally-generated longitudinal rail forces, is responsible for major track failures worldwide. The Bucklerisk model has shown ability to identify locatio...

Recently, there has been a movement in the railroad industry to begin assessing track geometry and track safety on the basis of real-time predictions of rail vehicle behavior in response to track geometry measurements while on board a track geometry car running at full track speed. With support from the Federal Railroad Administration, ZETA-TECH As...

The developments sponsored by FRA on the low cost means of increasing safe speeds through conventional AREMA turnouts are discussed. One criteria for the new turnout design was the requirement to maintain the existing turnout length. Since the maximum allowable track speed through the diverging leg of the turnout is based on the amount of lateral f...

The North American intermodal rail marketplace and ways to integrate technical engineering with strategic business planning to improve the economics of railroad business are discussed. Intermodal rail has been profitable on a lane specific basis, even including in North America. It is suggested that the lessons derived from the North American succe...

Presented are the results of Phase I of an FRA-sponsored study on low-cost means to increase safe speeds through turnouts by way of a retrofit or upgrade. Turnout lead length and frog angle were considered fixed, eliminating costs in relocating the frog or switch points. After in-depth research and dynamic simulation testing, it was determined that...

The use of transition grade-crossing design to reduce the impact in the transition from normal track to the stiffer grade-crossing structure was discussed. The design of the transition was based on the difference in stiffness between parent track. It was shown that the potential existed for eliminating 60 percent of the dynamic overloading in the c...

The use of wayside load measurement sites to monitor vertical and/or lateral wheel/rail forces has been in active use in North America for many years. Recently interest has increased in establishing a network of such sites to allow for the monitoring of railway cars that generate excessive levels of vertical and/or lateral loads. This would potenti...

A real-time dynamic simulation system designed to identify sections of track geometry that are likely to cause unsafe rail vehicle response is discussed. Known as TrackSafe, this system operates onboard a track geometry vehicle where the geometry measurements are passed as inputs to the dynamic model of one or more rail vehicle types. In order to c...

This paper presents the results of combined analytical and field study of the use of vertical stiffness transition zones to reduce dynamic wheel/rail impact forces at the interface between conventional track and high/rail grade crossings. These interfaces are traditionally sites of severe dynamic impact forces and corresponding rapid degradation of...

Ownership of the U.S. rail industry is divided between eight Class I railroads (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% of the 273,700 track-km (170,000 track-mi) and account for about 90% of industry revenues. The remaining 30% of track-km belon...

This paper presents the results of combined analytical and field study of the use of vertical stiffness transition zones to reduce dynamic wheel/rail impact forces at the interface between conventional track and high/rail grade crossings. These interfaces are traditionally sites of severe dynamic impact forces and corresponding rapid degradation of...

Modern rail grinding techniques use carefully applied grinding patterns to profile the rail head, and thus determine where and how wheel/rail contact will occur. Computer control has made possible this fine tuning of wheel/rail contact geometry, which reduces damage to the rail head and thus extends in-service life. However, it should be remembered...

Summary The selection of the optimum track system configuration is very much dependent on the performance requirements and economic characteristics of the rail operation that is being configured. One of the key decisions in selecting an appropriate track system is the selection of the proper cross-tie (sleeper)/fastener system. The range of availab...

During the last decade research has focused on new and improved track inspection techniques to define the conditions of the track structure and its key components. Among the areas of focus for this research have been inspection of the strength or load-carrying ability of the track structure and inspection of the cross-ties and cross-tie/fastener sy...

Turnout maintenance represents a significant expense and impact on railroad operations. Maintenance requirements and costs are expected to increase, as axle loadings increase. Recently, a research was conducted to examine the effect of heavy-axle-load operations on turnout component life, and corresponding maintenance costs. It was found that turno...

Research, under the sponsorship of Burlington Northern, has led to the development of the Tiescan wood-tie-condition measurement system. The system relies on sonic compression and tangential waves the condition of the wood in the zone between the transmitter and the receiver. When applied to the rail seat of a crosstie, a transmitter is placed on o...

As railroads strive to improve the overall cost-effectiveness of their various maintenance activities, methods for extending the life of key (and expensive) track components are continuously being studied and tried. The conventional wood crosstie is one such component that is undergoing investigation. Techniques for the extension of the life of tra...

The primary techniques used to investigate roadbed conditions include general observation of the track and 'destructive' investigations of the roadbed, such as cross-trenching and boring. Research over the last several years has led to the development of an alternate technique for investigations of ballast and subgrade conditions. The technique use...

Traditionally, railroad product purchasing decisions rest upon two factors: performance and cost. Performance implies the ability of the product or component to carry out its function adequately and effectively, while cost refers both to purchase price and maintenance fees. As loadings and traffic densities continue to increase, the costs associate...

Recent research indicates that the rail laying temperature is not constant with time. It appears to vary as a function of traffic and maintenance activity, and has an overall tendency to decrease. This results in rail neutral temperature that is below the rail laying temperature. Correspondingly, there is a greater potential for high longitudinal c...

Track measurement technology has advanced to the point where it is now possible to obtain reliable information about the condition of the head of rail. This data can be derived for a large stretch of track, or even an entire railroad. Such modern systems now include the capability of measuring both the transverse and longitudinal profiles of the ra...

The thermite welding process is the most widely used field welding procedure in North America. When properly performed, it will produce welds of 'suitable strength and integrity' for railroad use. However, the welds obtained are characterized by low ductility and low impact toughness. In addition, if the thermite welds are 'improperly made,' castin...

It is the purpose of this paper to concentrate on the performance requirements of fastener systems in track from the point of view of examining the role of and the requirements for the fastening system. It is not the intention of this paper to define performance specifications or performance tests, but rather to look at the role of the fastener in...

A recent alternative approach suggests that the inspection interval be varied as the rail ages. Specifically, as the rail accumulates tonnage, the interval between rail flaw inspections (either in time or in tonnages) should be decreased. By properly decreasing this interval as the rail ages, and thus becomes more prone to developing fatigue defect...

The monitoring of the railhead profile, to include both the railhead dimensions and the railhead shape, provides the following information: wear, profile, and metal removal (by grinding or other non-wear mechanisms). Measurement of railhead wear (or its converse, the remaining rail section) has been carried out traditionally by using a variety of h...

This paper presents a study of the mechanics of a rail-tie structure, as described by the new equations recently derived by the authors. It is shown how the rotational fastener stiffness, the flexural stiffness of the cros-ties, and the gage affect the lateral response of the rail-tie structure. In order to establish the validity of the new equatio...

Modern railroad track is called upon to withstand increasing axle loads and tonnages. As a result, rail maintenance has emerged as a key part of track maintenance programs. With industry rail costs approaching three quarters of a billion dollars, railroads can no longer afford to lay rail in track and leave it there until it fails. Railroads are ha...

An analytical model for examining the dynamic equilibrium is utilized to determine the lateral deflection and rotation of the rail subjected to time dependent lateral and vertical forces, and constant axial force. Galerkin's method was applied to remove the partial dependents of the differential equations of motion. The method resulted in a system...

Physical phenomena are reviewed to establish a basis for measuring longitudinal force. Various nondestructive testing techniques were considered, and it was concluded that no one of them applied singly is capable of providing an unambiguous practical measurement. Short-, medium-, and long-term recommendations are made, and the continued development...

Early analyses of the lateral response of cross-tie railroad tracks are based on the assumption that the rail-tie structure responds like a beam in bending. Because of the difficultiese encountered in determining the lateral bending stiffnes of a cross-tie track, a more recent approach is to model the rail-tie structure as a beam in bending that is...

Gage 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 improv...

A mathematical model of rail overturning was developed. This model together with other defined parameters of the rail fasteners are utilized to investigate several case studies of dynamic behavior of the rail. Comparison between these dynamic cases and static tests has been done. It is recommended that multiple axial load should be considered in th...

An analytical model for examining the dynamic behavior of rail overturning is developed. The mathematical model of the rail track system and dynamic equilibrium is utilized to determine the lateral deflection and rotation of the rail subjected to time dependent lateral and vertical forces and constant axial force. Galerkin's method was applied to r...

The paper summarizes the background, accomplishments, and scheduled test activities of the Track Strength Characterization Program. Recent data from laboratory tests on a track section at the AAR's Track Structures Dynamic Test Facility and pilot studies of field measurement facilities are reviewed. Details of scheduled field characterization tests...

This paper presents the results of a series of tests and analyzes directed towards the characterization of the track structure under vertical loads. It also presents and evaluates different analytical techniques for the calculation of the vertical track modulus.

The paper contains a study of two models which represent the mechanisms of gage widening and rail roll in a track subjected to vertical, lateral, and longitudinal loading. The deformation mechanisms of the rail-fasteners-tie system under service loads was investigated, and the results compared with track test data. It was found that two distinct de...

http://trid.trb.org/view.aspx?id=81551 Free vibration characteristics of a rail flat car structure were investigated in Volume I using three different finite element models. These models were validated through the comparison of the predicted vibration mode shapes and frequencies with test results. Further validation of the models is performed here...

An analytical model for examining the dynamic behavior of rail overturning has been developed by the authors in another paper. This mathematical model of the rail-track system and dynamic equilibrium is utilized to determine the lateral deflection and rotation of the rail subjected to time-dependent lateral and vertical forces and constant axial fo...

This paper introduces a methodology for the calculation of the fatigue life of rails in service. In this methodology, a service environment is represented by means of an environmental load spectra, which is then converted to stresses at the rail. In this analysis, the rail fatigue life at several stress levels is calculated for various rail section...

The matching of wood species to specific railroad operating and environmental conditions has long been recognized as a desirable goal in optimizing the use of wood cross-ties in track. In fact, several North American railroads currently use a limited form of species segregation in an attempt to match wood performance and operating and environmental...