This paper presents the results of combined analytical and field study of the use of vertical sti... more 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 the geometry of the track. A recent FRA sponsored research study developed a new analytical technique to define the number of and magnitude of the stiffness transition zones needed to reduce the dynamic impact forces. This technique was used to design a series of transitions for a concrete grade crossing, which were installed on New Jersey Transit’s Atlantic City Line in the vicinity of ATCO New Jersey in 1998. Field tests performed on the grade crossing after installation showed a significant reduction in measured dynamic vertical accelerations across the grade crossing as compared to other crossings on the same line. Recent follow up ev...
New technologies and improved grinding practices along with improved understanding of the wheel/i... more New technologies and improved grinding practices along with improved understanding of the wheel/interface relationship make it increasingly important for grinding control systems to analyze different grinding pattern performances. These new technologies have created a need to model the rail process both individually and in complex situations that will result in better management of the grinding process and improved planning of grinding activities. The first approach for the analysis of metal removal on the rail head uses a "closed" mathematical representation of the rail head where the shape of the rail head is defined according to the design radii. The second approach uses a digitized rail profile that is taken from a modern rail profile measurement system. Both cases require definition of the three-dimensional coordinate system of the grinding wheel moving along the axis of the rail head. While errors in collection of some of the profiles have resulted in missing zones i...
This paper presents the results of a study on the optimization of ballast placement planning, pri... more This paper presents the results of a study on the optimization of ballast placement planning, prioritization and management for railway ballast distribution. Specifically, this paper presents the requirements for and inputs necessary to more effectively manage the ballast placement process and take advantage of the new track inspection technologies that provide more accurate and reliable data about ballast condition and track profile. This is to include addressing such key issues as: x Where and how much ballast should be placed; to include ballast at end of ties (shoulders), under ties, and in cribs. x How much ballast should be placed; to include reference or required ballast profile based on vertical, lateral and longitudinal performance requirements A key portion of this study was the introduction of new inspection technologies now available to more accurately define the ballast requirements. This includes such newly introduced inspection technologies as LIDAR for measurement of...
The price of wood cross-ties is dependent on the availability of timber, the competition with use... more The price of wood cross-ties is dependent on the availability of timber, the competition with uses for other timber products cut from the same logs, and railroad usage of cross-ties. This project examines the historical prices of wood cross-tie as a function of key timber tie industry factors such as monthly and annual timber tie production, monthly and annual inventories, and the price of green 4/4 2A oak board per foot. This paper uses detailed data from a multi-year period and a statistical analysis was performed of the relationship between hardwood cross-tie prices and the key timber industry parameters. The resulting sensitivity of the tie price to these factors and the associated "predictive" relationship is presented together with the potential impact on railroad tie purchasing practices and behavior. The project examines the effect of changes in railroad purchasing practices which may provide for more stable tie prices in terms of the life cycle costs of alternate ...
As vehicle operating speeds increase, the dynamic wheel/rail impact forces applied to the track s... more As vehicle operating speeds increase, the dynamic wheel/rail impact forces applied to the track structure likewise increase. This results in the potential for increased track degradation, component failure, and corresponding increased track maintenance costs. In the case of Amtrak’s new generation high speed trains, a specific requirement for the design of the new equipment was to avoid any increase in dynamic forces applied to the track in spite of the increase in operating speed from 125 to 150 mph. In order to achieve this, and maintain (or possibly decrease) the dynamic wheel/rail forces, key equipment design characteristics, to include vehicle unsprung mass and suspension characteristics, were evaluated from this point of view. This report describes the process of examining alternative high-speed equipment designs from the perspective of the track structure and the level of dynamic force applied to the track. This includes the process used to evaluate the dynamic wheel/rail for...
This article will describe how rail grinding can help to modify and optimize the wheel/rail conta... more This article will describe how rail grinding can help to modify and optimize the wheel/rail contact configuration, as well as its associated contract stress state. The wheel/rail interface represents a complex operating and loading environment with different contact configurations and associated stress configurations. The article shows how these contact and stress configurations vary as a function of such key track and operating parameters as track curvature and super-elevation, train speed, and wheel and rail condition. The associated stress environment includes the critical wheel/rail contact stresses, as well as additional stresses from rail bending, thermal loading and train braking and acceleration. These contact stresses are critical in defining the life and performance of the rail. Rail profile grinding and its associated improved wheel/rail interaction control have been credited with dramatic increases in rail life in Western Australia. This represents a multi-fold increase ...
One clear application of this approach is that of the crossties and fastener systems, specificall... more One clear application of this approach is that of the crossties 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.
This article shows that proper management of the grinding speed can allow for control of metal re... more This article shows that proper management of the grinding speed can allow for control of metal remover to optimize the effectiveness of the rail grinding operations. In particular, this allows for the implementation of high-speed preventive maintenance grinding that uses shallow, fast and frequent grinding passes to control the rail profile, the wheel/rail interface and the development of rail defects.
This article focuses on risk management techniques as an effective tool in controlling broken rai... more This article focuses on risk management techniques as an effective tool in controlling broken rail derailments. It relates that identifying key parameters or sets of parameters that help identify high risk locations is a key element in risk management. The article also discusses developing a broken-rail risk parameter and associated guidelines for reducing the risk of broken-rail derailments.
As transit vehicle wheels accrue mileage, they experience flange and tread wear based on the cont... more 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 practice is truing; using a specially designed cutting machine to bring a wheel back to an acceptable profile. This process removes metal from the wheel and is often based on wheel flange thickness standards (and sometimes wheel flange angle). Wheel replacement is usually driven by rim thickness, which is continually reduced by wear and metal removed by truing. This research study used wheel wear data provided by the New York City Transit Authority (NYCTA) to analyze wheel wear trends and forecast wheel maintenance (truing based on flange thickness) and wheel life (replacement based on rim thickness). Using automatic wheel-scanning technology, NY...
This paper presents the results of a series of track gauge widening tests conducted at the Associ... more This paper presents the results of a series of track gauge widening tests conducted at the Association of American Railroad's Track Structures Dynamic Test Facility. The tests investigated the gauge widening behaviour of conventional track structure under various combinations of vertical, lateral and longitudinal loads. The effect of single axle vs dual-axle loading and static vs dynamic lateral loading were also examined. The tests indicated that under loading representative of that imposed by traffic, significant widening of the track gauge can occur. It was further observed that the level of damage to the tie--fastener interface can be measured and evaluated by means of gauge widening type testing and that the potential exists for conducting "nondestructive" gauge widening tests in service track.
This research studies the development of lateral thermal expansion forces on a curved railway tra... more 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. Th...
This paper introduces a methodology for calculation of the fatigue life of rails in service. Incr... more This paper introduces a methodology for calculation of the fatigue life of rails in service. Increased wheel loads has increased fatigue-related problems. A service environment is represented by means of an environmental load spectra which is then converted to stresses at the rail. Although the paper is limited to flexural rail stresses, the methodology can be extended to other states of stress. Once the spectra is established, rail life is calculated by means of Miner's linear cumulative damage theory. Along with showing the detrimental effect of increased wheel loads, the need for matching rail size to loads is necessary to minimize rail defects.
In today's era of system optimization and cost sensitivity, proper planning and management of... more In today's era of system optimization and cost sensitivity, proper planning and management of track maintenance can be an important tool in helping railroads control capital and maintenance costs, especially for high capital cost items such as rail. As the cost of maintenance continues to rise, the ability to properly plan and execute track maintenance programs in an efficient and cost-effective manner becomes more and more important. Recent advances in software and analysis techniques offer new opportunities for track maintenance planning, and with this in mind, the article explains how vast quantities of inspection data can be interpreted and harnessed to optimize maintenance activities.
This paper presents the results of combined analytical and field study of the use of vertical sti... more 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 the geometry of the track. A recent FRA sponsored research study developed a new analytical technique to define the number of and magnitude of the stiffness transition zones needed to reduce the dynamic impact forces. This technique was used to design a series of transitions for a concrete grade crossing, which were installed on New Jersey Transit’s Atlantic City Line in the vicinity of ATCO New Jersey in 1998. Field tests performed on the grade crossing after installation showed a significant reduction in measured dynamic vertical accelerations across the grade crossing as compared to other crossings on the same line. Recent follow up ev...
New technologies and improved grinding practices along with improved understanding of the wheel/i... more New technologies and improved grinding practices along with improved understanding of the wheel/interface relationship make it increasingly important for grinding control systems to analyze different grinding pattern performances. These new technologies have created a need to model the rail process both individually and in complex situations that will result in better management of the grinding process and improved planning of grinding activities. The first approach for the analysis of metal removal on the rail head uses a "closed" mathematical representation of the rail head where the shape of the rail head is defined according to the design radii. The second approach uses a digitized rail profile that is taken from a modern rail profile measurement system. Both cases require definition of the three-dimensional coordinate system of the grinding wheel moving along the axis of the rail head. While errors in collection of some of the profiles have resulted in missing zones i...
This paper presents the results of a study on the optimization of ballast placement planning, pri... more This paper presents the results of a study on the optimization of ballast placement planning, prioritization and management for railway ballast distribution. Specifically, this paper presents the requirements for and inputs necessary to more effectively manage the ballast placement process and take advantage of the new track inspection technologies that provide more accurate and reliable data about ballast condition and track profile. This is to include addressing such key issues as: x Where and how much ballast should be placed; to include ballast at end of ties (shoulders), under ties, and in cribs. x How much ballast should be placed; to include reference or required ballast profile based on vertical, lateral and longitudinal performance requirements A key portion of this study was the introduction of new inspection technologies now available to more accurately define the ballast requirements. This includes such newly introduced inspection technologies as LIDAR for measurement of...
The price of wood cross-ties is dependent on the availability of timber, the competition with use... more The price of wood cross-ties is dependent on the availability of timber, the competition with uses for other timber products cut from the same logs, and railroad usage of cross-ties. This project examines the historical prices of wood cross-tie as a function of key timber tie industry factors such as monthly and annual timber tie production, monthly and annual inventories, and the price of green 4/4 2A oak board per foot. This paper uses detailed data from a multi-year period and a statistical analysis was performed of the relationship between hardwood cross-tie prices and the key timber industry parameters. The resulting sensitivity of the tie price to these factors and the associated "predictive" relationship is presented together with the potential impact on railroad tie purchasing practices and behavior. The project examines the effect of changes in railroad purchasing practices which may provide for more stable tie prices in terms of the life cycle costs of alternate ...
As vehicle operating speeds increase, the dynamic wheel/rail impact forces applied to the track s... more As vehicle operating speeds increase, the dynamic wheel/rail impact forces applied to the track structure likewise increase. This results in the potential for increased track degradation, component failure, and corresponding increased track maintenance costs. In the case of Amtrak’s new generation high speed trains, a specific requirement for the design of the new equipment was to avoid any increase in dynamic forces applied to the track in spite of the increase in operating speed from 125 to 150 mph. In order to achieve this, and maintain (or possibly decrease) the dynamic wheel/rail forces, key equipment design characteristics, to include vehicle unsprung mass and suspension characteristics, were evaluated from this point of view. This report describes the process of examining alternative high-speed equipment designs from the perspective of the track structure and the level of dynamic force applied to the track. This includes the process used to evaluate the dynamic wheel/rail for...
This article will describe how rail grinding can help to modify and optimize the wheel/rail conta... more This article will describe how rail grinding can help to modify and optimize the wheel/rail contact configuration, as well as its associated contract stress state. The wheel/rail interface represents a complex operating and loading environment with different contact configurations and associated stress configurations. The article shows how these contact and stress configurations vary as a function of such key track and operating parameters as track curvature and super-elevation, train speed, and wheel and rail condition. The associated stress environment includes the critical wheel/rail contact stresses, as well as additional stresses from rail bending, thermal loading and train braking and acceleration. These contact stresses are critical in defining the life and performance of the rail. Rail profile grinding and its associated improved wheel/rail interaction control have been credited with dramatic increases in rail life in Western Australia. This represents a multi-fold increase ...
One clear application of this approach is that of the crossties and fastener systems, specificall... more One clear application of this approach is that of the crossties 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.
This article shows that proper management of the grinding speed can allow for control of metal re... more This article shows that proper management of the grinding speed can allow for control of metal remover to optimize the effectiveness of the rail grinding operations. In particular, this allows for the implementation of high-speed preventive maintenance grinding that uses shallow, fast and frequent grinding passes to control the rail profile, the wheel/rail interface and the development of rail defects.
This article focuses on risk management techniques as an effective tool in controlling broken rai... more This article focuses on risk management techniques as an effective tool in controlling broken rail derailments. It relates that identifying key parameters or sets of parameters that help identify high risk locations is a key element in risk management. The article also discusses developing a broken-rail risk parameter and associated guidelines for reducing the risk of broken-rail derailments.
As transit vehicle wheels accrue mileage, they experience flange and tread wear based on the cont... more 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 practice is truing; using a specially designed cutting machine to bring a wheel back to an acceptable profile. This process removes metal from the wheel and is often based on wheel flange thickness standards (and sometimes wheel flange angle). Wheel replacement is usually driven by rim thickness, which is continually reduced by wear and metal removed by truing. This research study used wheel wear data provided by the New York City Transit Authority (NYCTA) to analyze wheel wear trends and forecast wheel maintenance (truing based on flange thickness) and wheel life (replacement based on rim thickness). Using automatic wheel-scanning technology, NY...
This paper presents the results of a series of track gauge widening tests conducted at the Associ... more This paper presents the results of a series of track gauge widening tests conducted at the Association of American Railroad's Track Structures Dynamic Test Facility. The tests investigated the gauge widening behaviour of conventional track structure under various combinations of vertical, lateral and longitudinal loads. The effect of single axle vs dual-axle loading and static vs dynamic lateral loading were also examined. The tests indicated that under loading representative of that imposed by traffic, significant widening of the track gauge can occur. It was further observed that the level of damage to the tie--fastener interface can be measured and evaluated by means of gauge widening type testing and that the potential exists for conducting "nondestructive" gauge widening tests in service track.
This research studies the development of lateral thermal expansion forces on a curved railway tra... more 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. Th...
This paper introduces a methodology for calculation of the fatigue life of rails in service. Incr... more This paper introduces a methodology for calculation of the fatigue life of rails in service. Increased wheel loads has increased fatigue-related problems. A service environment is represented by means of an environmental load spectra which is then converted to stresses at the rail. Although the paper is limited to flexural rail stresses, the methodology can be extended to other states of stress. Once the spectra is established, rail life is calculated by means of Miner's linear cumulative damage theory. Along with showing the detrimental effect of increased wheel loads, the need for matching rail size to loads is necessary to minimize rail defects.
In today's era of system optimization and cost sensitivity, proper planning and management of... more In today's era of system optimization and cost sensitivity, proper planning and management of track maintenance can be an important tool in helping railroads control capital and maintenance costs, especially for high capital cost items such as rail. As the cost of maintenance continues to rise, the ability to properly plan and execute track maintenance programs in an efficient and cost-effective manner becomes more and more important. Recent advances in software and analysis techniques offer new opportunities for track maintenance planning, and with this in mind, the article explains how vast quantities of inspection data can be interpreted and harnessed to optimize maintenance activities.
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