Forward-Looking Infrared Radiometry (FLIR) Application for Detecting Ballast Fouling

This paper is intended to assess the practical aspects of the previously proposed approach for detecting railroad ballast fouling using an off-the-shelf Forward-Looking Infrared Radiometry (FLIR) Technology. FLIR is among the technologies that are becoming more prevalent in railroad applications [1,2]. The method discussed in this paper takes advantage of the temperature differences measured by the FLIR camera between the top surface of clean and partially fouled ballast samples as an indicator of fouling. The method is intended to potentially serve as an efficient and time-effective manner for detecting early stages of ballast fouling prior to it requiring a costly intervention. Ballast fouling is a common maintenance-of-way issue for the railroad industry, which occurs as a result of contaminants clogging up the ballast and preventing water drainage. The water retained at the sublayers diminishes the strength of the foundation and could result in other undesirable conditions such as clay pumping and reduced track strength. In this study, experiments are performed to study the thermal behavior and characteristics of clean, and partially- and fully-fouled ballast using a FLIR camera. The FLIR camera is set up in a stationary configuration for ease of testing and also providing a more direct approach to analyzing the data, to keep the test conditions highly repeatable and reduce any environmental variations. The results indicate that the cooling and heating rate at the top surface for clean, partially fouled, and fouled ballast are different during the daily heat-up cycle. It is determined that although the FLIR camera is able to measure some changes in the ballast temperature for the fouling conditions that are evaluated in the study, the differences may be within the range of variations that could occur in field conditions. The paper includes the range of measured temperature by the FLIR camera and discusses the pros and cons of using this approach in practice. Additional field testing is needed to validate or dispute the initial findings of the study.

Development of a parametric model for the prediction of concrete railway crosstie service bending moments

Concrete crosstie usage in North America continues to increase for rail transit and heavy axle load freight railroad applications. As such, it is important to design optimized crossties to save both capital and maintenance funds. Recently, a method for quantifying concrete crosstie bending moments using concrete surface strain gauges has been developed, deployed, and validated. Data from this method are used in this paper for (1) building a model to quantify sources of variability for field bending moments and the relative influence of each source, (2) generating an accurate model to predict bending moments at the two field locations surveyed, and (3) comparing the relative effects of predictor variables on rail transit and heavy axle load freight rail modes to determine their influence on service bending moments. Results show that it is possible to develop a reliable model to predict bending moments, and that several factors have a strong influence on these predictions, namely vertical load, temperature gradient, and axle location within a railcar truck. The most significant factor is the crosstie support condition, especially with respect to center moments. While the aforementioned model’s primary utility is for the two sites and railroad systems surveyed, the model provides a valuable tool for determining which variables are the most critical for inclusion in the future mechanistic design of concrete crossties.

Manage Successful Brownfield Applications

This paper provides a unique perspective on successful brownfield railroad applications. It presents realistic challenges and solutions when applying a turnkey solution with a replacement or an overlay system. Brownfield commissioning takes place when an existing infrastructure is to upgrade to a new system with a different technology than the incumbent one. As signaling systems are getting more and more complex, it is extremely important to maintain robustness in the system design as well as project execution, such as logistics, documentation, and issue reporting. Many transportation authorities are moving from their current train control signaling system to a new system to combat obsolescence issues, to gain better system capacity, and to lower operation and maintenance costs. This paper discusses brownfield commissioning in general, and also presents specific cases in migration from a track circuit interlocking system to a Communications Based Train Control (CBTC) system. These two systems have distinct characteristics that provide opportunities of coexistence, but also introduce difficulties in mixed-mode operations.

Laboratory Development and Testing of “SmartRock” for Railroad Ballast Using Discrete Element Modeling

Ballast aggregate settlement is generally a result of consolidation or rearrangment of ballast particles in the area underneath crossties. Excessive settlement negatively impacts track performance, resulting in increased risk of train derailment. The purpose of this paper is to compare two methods to evaluate ballast aggregate settlement with repeated loading in railroad: discrete element modeling and laboratory tests using “SmartRock”. In this study, ballast aggregates are considered as uniformly graded, angular shaped with crushed faces. For the discrete element modeling, digital imaging techniques are utilized to create the ballast aggregates. Aggregate settlement in railroad ballast and the effect of aggregate shape on the dynamic response of ballast are evaluated through the discrete element simulations. A wireless device, “SmartRock” is developed to study the relationship between individual ballast particle behavior and overall ballast performance. It has a shell of a typical ballast particle shape with force cells attached on the surface and embedded with a tri-axial gyroscope, a tri-axial accelerometer, and a tri-axial magnetometer. The device can move under train traffic like a real ballast particle and record inter-particle contact forces and particle motion in real time. For the laboratory tests, a model-scale track section is constructed and subjected to repeated loading similar to train traffic. The developed “SmartRock” are embedded below rail seats and in the track shoulders. The laboratory data using “SmartRock” can be compared with results from the discrete element modeling in the future. These comparisons will validate the discrete element modeling procedure as a means to analyze railroad ballast aggregate behavior and the potential of “SmartRock” in railroad applications.

Rotational Energy Harvesting Systems for Unpowered Freight Rail Cars

Commonly, freight cars have no available source of electric power, thus preventing the use of any electronic devices that could improve convenience, performance, and efficiency of railroad operations. The devices introduced in this paper are motion-based electromagnetic energy harvesting systems. Similar in size and shape to a conventional damper or shock absorber, the systems are to be placed in the coil spring of the suspension to convert part of the energy usually wasted as heat into useful electric energy. This paper will present the design, development and testing of such devices. Tests of prototype devices on a shock dynamometer show that more than 20 Watts RMS of power can be produced with motions that can be encountered in train suspensions. The devices presented, although primarily developed for railroad applications, are not limited to use in freight cars and could be similarly applied in various vehicles with suspension like tractor-trailers, buses or automobiles.