Joseph W. Palese

Increasing Speeds Through the Diverging Route of a Turnout Without Increasing Lead Length

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 best approach was to optimize existing American Railway Engineering and Maintenance of Way Association (AREMA) turnout geometry. This required a new diverging switch rail and reshaping both the curved stock and closure rails. This low-cost modification applies to most existing turnouts and is expected to improve ride quality and decrease wear without detriment to current maintenance practices. The optimization of a conventional AREMA #20 turnout with straight switch points is discussed as an example. The best vehicle performance in simulations was achieved by a design having a very low entry angle. Vehicle behavior at a speed of 51 mph was significantly improved over the AREMA straight point design at its speed limit of 36 mph, as well as that of the AREMA curved point design at its limit of 50 mph. Also, simulated vehicle performance was nearly as good as for a #20 tangential turnout that has a 20 ft longer lead length. Finally, there was improved performance at speeds as high as 60 mph without exceeding any established safety limits. From these results, a turnout with the reshaped geometry has been constructed and is scheduled for installation on New Jersey Transit.

Analysis of Wheel-Rail Contact Stresses Through a Turnout

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 stresses vary as a vehicle negotiates the turnout. This paper presents the results of a series of analyses and computer simulations developed to examine the wheel/rail contact behavior as a vehicle negotiates a turnout and to determine the location and magnitude of the associated wheel/rail contact stresses. These analyses include a procedure for aligning the wheelset profile to the rail profile pair, based on the actual rail profiles, as it varies through the turnout. Using the point-by-point alignment, the analyses then determine the location of the wheel/rail contact patch and then calculate the magnitude of the contact stress profile in that patch. The result is a map of the wheel/rail contact stress as a vehicle moves through the turnout.Copyright

Performance of a Track Geometry Car-Based Real-Time Dynamics Simulator Using Multiple Vehicle Types

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 comprehensively analyze the effect of the existing geometry on rail vehicle behavior, the system is capable of simultaneously simulating the response of several vehicle models, each over a range of traveling speeds. The resulting response predictions for each modeled vehicle and each simulated traveling speed are used to assess the track geometry condition and to identify locations leading to potentially unsafe response. This paper presents the latest work in the development of TrackSafe, specifically, the development and testing of eight new vehicle models is presented. The new car types modeled include a box car, flat car, and both a long and short tank car. Each can be simulated in a fully loaded or empty condition. Accuracy of the models is discussed in detail.Copyright

Optimizing Tamper Efficiency Through the Integration of Inertial Based Track Geometry Measurement

Maintaining track geometry is key to the safe and efficient operations of a railroad. Failure to properly maintain geometry can lead to costly track structure failures or even more costly derailments. Currently, there exists a number of different methods for measuring track geometry and then if required, maintaining the track to return track geometry to specified levels of acceptance. Because of this need to have proper track geometry, tampers are one of the most common pieces of maintenance equipment in a railroad operation’s fleet. It is therefore paramount from both a cost and track time perspective to gain maximum efficiency from any one particular tamper.Track geometry is typically measured through a variety of contact and non-contact measurement systems which can mount on a variety of different platforms. With respect to a tamper, a push buggy projector system is typically used to measure track geometry, utilizing the tamper body as the basis for the reference system, Track geometry can be measured utilizing this technology during a prerecording run. Then, the software onboard the tamper analyzes the recorded data to determine the best fit and calculate throws that achieve a better track alignment, particularly in curves. During the tamping operation, the tamper buggy system and frame adjust the track. Due to its design, track geometry measurements can only be made at low speed (roughly 4mph) which can severely affect the efficiency of the tamper. To help decrease pre maintenance inspection times, an inertial based track geometry measurement system has been developed and integrated into the tamper’s operating software. This system can mount directly to the frame of a tamper and operate at hy-rail to very low speeds. Measurements made can be fed directly into the tamper control system to guide where and how track geometry adjustments need to be made.In addition, the capability to collect data during travel mode without the buggies extended allows for the collection of data at any time. Thus, data can be recorded when traveling back and forth to a stabling location, before and/or after grinding. This allows for synchronization of data at a later time to utilize for adjusting the track. Also, data can be collected post-work to allow for the comparison of pre and post geometry to allow for the determination of the effectiveness of a given tamping operation.Tampers equipped with this track geometry system facilitate the foundation for an enterprise solution. Data that is measured and collected can be sent to a cloud service, in real time that will provide exception reports, health status, and rail health trend analyses. Utilizing the available technology further optimizes response time in track maintenance.This paper will introduce this new method of mounting and completely integrating an inertial based track geometry system onto a tamper. In addition, studies will be presented which confirm the ability of this system to replicate the tamper’s projection based track geometry system. Finally, a comprehensive study on efficiency gains will be presented directly comparing a standard method of maintaining a segment via a tamper to this new method of using onboard inertial track geometry measurement.© 2017 ASME