Use of Archard’s Wear Law for the Calculation of Uniform Wheel Wear of High Tonnage Freight Vehicles

Wheel profile evolution has a large influence on track and wheelset related maintenance costs. It influences important parameters such as equivalent conicity or contact point positioning, which will affect the dynamic behavior of the vehicle, in both tangent track and curve negotiation. High axle loads in freight wagons may increase both the wheel wear and the damage caused by vehicles with both new and already worn profiles. A common profile in Europe is the S1002 profile, developed for rail inclination 1/40. In Sweden rail inclination is 1/30, so contact conditions might not be optimal. The presented work uses Archard’s wear law to analyze the profile wear evolution in a two axle freight vehicle with Unitruck running gear on the Swedish network. This wear calculation methodology has been successfully used to predict uniform wear in passenger vehicles. First, the vehicle model has been optimized in order to improve the speed of the wear simulations. Experimental measurements of wheel profiles have been performed in order to validate the simulations. The conclusion is that the wear methodology successfully used to predict uniform wheel wear in passenger vehicles cannot be directly applied for the calculation of wheel profile evolution in high tonnage freight vehicles. The influence of block brakes or switches and crossings cannot be dismissed when calculating uniform wheel wear in these cases.

Analysis of Brake Failure and Runaway Accidents in Mountain Terrain in Canada

A number of serious rail runaway accidents have occurred in recent years on long and high grade downhill tracks in mountain terrains in Canada, causing fatal injuries and huge property loss. They were caused by brake failure, misunderstanding of brake features, maintenance deficiency and/or improper brake application on the trains. Train dynamics simulation, brake ratio testing, and dynamometer testing on friction heat fade helped disclose the causes and contributing factors in the cases presented in this paper. Guidelines were revised for safer train operation, equipment requirements and maintenance practice in the mountain terrain conditions.

Survey and Examination of Various CBTC Data Communications Subsystems

This paper will survey and describe the various data communication subsystems (DCSs) used on many communications based train control (CBTC) system projects planned and in service throughout North America, Europe and Asia. The paper will focus on the RF characteristics of the DCS so as to highlight the similarities and common challenges that all DCSs face with a view to presenting best practice and innovative design.

Comparison Between Wayside Storage and Reversible Thyristor Controlled Rectifiers (RTCR) for Heavy Rail Applications

There had been a substantial interest in the traction community to use wayside Energy Storage Systems (ESS) to better utilize train braking energy and thus achieve reduction of energy cost and peak power, and voltage stabilization. An alternative solution to reach the same goals is using recuperating (also called regenerating) traction power stations such as a Reversible Thyristor Controlled Rectifiers (RTCR). The paper compares advantages and disadvantages of ESS of three most common types — flywheels, batteries and supercapacitors — and RTCR. The analysis takes into account size, capital cost, the “round trip” energy losses and energy savings for heavy rail applications.

Modification of the Relation Between Grade and Curvature — Purpose, Reasons, and Advantages

In cases where grades and horizontal curves are combined, the current relation between the grade and the degree of curve, D, is defined as follows:G+cD=r in which G = The maximum allowable compensated grade in %, D = Degree of curve, c = 0.04, compensation factor in % grade per degree of curve, r = The maximum grade achievable by the train in %. The above relation is a design tool to combine grade and curvature. The author intends to modify the above relation for two purposes — • to make the relation more rational for combining grade and curve for LRT design, and • to make the relation useful in computing the installation slope of special trackwork. A modified formula is suggested as under:G+cD=kr in which c = compensation factor in % grade per degree of curve determined on the basis of curvature, k = grade reduction factor arbitrarily chosen between 0.2 ∼ 1 depending on curvature and type of rail. The justification of the proposed modification and the advantages of the modified formula are discussed in details.

Abandoned Freight Rail Corridor Reuse Examples From Texas

This paper highlights many varied reuse examples for abandoned freight rail corridors within the state of Texas, including for highway development, transit development, recreational trails, and for resumption of freight rail service. Several case studies present these examples. This paper also describes the extent to which abandoned rail lines in the state have been lost through abandonment and discusses the importance of preserving such corridors intact, when possible, for future transportation needs should any become available in the future.

Prediction of Railroad Track Foundation Defects Using Wavelets

This paper presents a novel technique that utilizes wavelet analysis to identify and predict the defects in railroad foundations and rails to prevent derailment or other damages. The proposed defect detection algorithm eliminates the use of wheel and/or track monitoring systems, which are expensive and time inefficient. The algorithm has been validated for the rail crack prediction using only vertical accelerometer signal which accurately detects impending rail breakage while distinguishing the signal generated by special track components such as rail joins and switches. Since the algorithm is flexible, further development can be tailored to detect significantly different rail defects such as track shift and other rail foundation defects. The algorithm is further improved by incorporating SIMPACK dynamic simulation to assist classification of the acceleration signatures. The actual data was then compared to simulation in order to validate the effectiveness of the algorithm.

Quantitative Measurement of Pantograph Loss of Contact Dynamics

In this paper we present our work on the development of a quantitative measurement advice to capture the dynamics of pantograph arcing during loss of contact. Despite the difficulties involved, it is very important for the railroad operators to accurately measure the pantograph loss-of-contact dynamics in order to assess the current collection quality of the pantograph with the overhead contact system during the commissioning phase and long-term operation. We use photovoltaic cells to construct a simple but effective sensor that can produce a voltage signal proportional to arc strength and duration, which can then be used as a precise quantitative measure of the loss of contact dynamics of the pantograph.

Analysis of End Hose Elasticity

This paper investigates the relationship between end hose elasticity and the potential amount of energy coupled railroad cars can absorb in charged condition before pull a part force separation occurs. One of the most significant issues with the existing end hose is that it will uncouple after enough force is applied causing a loss of pressure in the brake system. Our initiative to evolve the end hose into a more durable wire braided rubber material from the standard hand wrapped construction has decreased this potential for separation in the field. Simulation testing using end hoses from three manufacturers is studied and compared. Charged hose assemblies were coupled and pulled apart. The results showed one end hose stretched nearly double the distance of the other hoses. Analysis of the resulting data will show that a more elastic hose will allow a train brake system to absorb more energy thus reducing the opportunity for a disconnect while in service.

Prestressing Steel Reinforcement Wire Bond Index Number

The purpose of this research project is to develop a mathematical model that predicts the bond strength of a prestressing steel reinforcement wire given the known geometrical features of the wire. The geometrical features of the reinforcement wire were measured by a precision non-contact profilometer. With this mathematical model, prestressing reinforcement wires can now be analyzed for their bond strength without destructive testing. This mathematical model has the potential to serve as a quality control assessment in reinforcement wire production. In addition this mathematical model will provide insight into which reinforcement wires provide the greatest bond strength and which combinations of geometrical features of the reinforcement wire are responsible for providing the bond strength. A precision non-contact profilometer has been developed to measure the important geometrical features of the reinforcement wire. The profilometer is capable of sub-micron resolution measurements to provide an extremely high quality three-dimensional rendering of the reinforcement wire surface profile. From this detailed profile data it is then possible to extract all of the relevant geometrical features of the reinforcement wire. A mathematical model has been created by testing a variety of different reinforcement wires available in the market. By correlating the transfer length of concrete prisms made with the reinforcement wires to various geometrical features, several different levels of mathematical correlation complexity have been investigated. The current empirical correlation models under development are first order and combine three to four unique geometrical features of the reinforcement wire which then act as predictors of the concrete prism transfer length. The resulting mathematical model relating the wire geometrical features to transfer length is referred to as the Bond Index Number (BIN). The BIN is shown to provide a numerical measure of the bond strength of prestressing steel reinforcement wire, without the need for performing destructive tests with the reinforcement wire.