A Novel Algorithm for Predicting Track Irregularities of Unit Track Sections

During train runs, the interaction between train wheels and the rail track underneath makes track geometry change, which in turn results in all kinds of track irregularities. After the 6th train speed raise of China in 2007, railway transportation has shown three main new features: speed-raised, heavy-loading and high-density. Under these features, changes in railway track irregularities of China have also presented some new characteristics: higher deterioration rates of track irregularities and more frequent occurrences of track exceptions. To ensure the train operational safety and increase the transportation service quality, the preventive inspection and maintenance of railway track facilities have been put forward once again by railway maintenance departments of China. A precondition for the preventive inspection and maintenance is about how to accurately evaluate and predict the future track condition according to the historical track inspection data. In this paper, based on the characteristics of track irregularity changes and in accordance with the calculus thinking, we have developed a short-range prediction model called SRPM. The model uses track waveform data generated by the track geometry car (TGC) to predict track irregularities of a unit track section with the length of 100m for each day in a future short period of time. An algorithm for using SRPM to predict track irregularities has also been designed. According to the designed algorithm, using ORACLE database and computer program languages, we have programmed a computer software named P-SRPM. We then used P-SRPM to deal with 25 sets of TGC-generated track waveform data from the up going track of the Beijing-Shanghai railway (Jing-Hu railway) administrated by Jinan Railway Bureau (JRB) and predicted track irregularities of unit sections in the railway track segment. Finally, errors in these predictions were analyzed in both temporal and spatial dimensions. From the error analysis results, we come to the conclusion that SRPM can fairly accurately make short-range predictions for track irregularities of each unit section in the JRB-administrated Jing-Hu railway track (up going).

Evaluating the Potential for Damaging Hydraulic Pressure in the Concrete Tie Rail Seat

Rail seat deterioration (RSD) is the most critical problem with concrete tie performance on North American freight railroads. Currently, the problem is not sufficiently understood to allow for effective solutions. RSD is considered to have up to five potential mechanisms, and this paper investigates one of them: hydraulic pressure cracking. A model of the effective stress in a concrete tie rail seat — considering the contributions of a uniform vertical load, a uniform lateral load, a prestressed beam on an elastic foundation, and pore pressure to the state of stress — was created to determine what surface water pressures at the rail seat could lead to damaging pore water pressures in the concrete. A laboratory test setup and procedure were devised to measure the surface water pressure in a laboratory rail seat using tie pads of differing material composition and geometry. Results show that the magnitude of the pressure generated and the rate of pressure dissipation with many load cycles depends on the pad material and surface geometry. Comparing the effective stress model and the measured surface pressures, hydraulic pressure cracking appears to be a feasible mechanism for RSD given the correct combination of dynamic rail seat loads, sufficient moisture, and a tie pad surface that develops high pressure.

Applied High Resolution Traffic Controller Data Outcome Based Performance Measures With Gate-Down Confirmation Circuit

Track clearance green phases are used at railroad preempted intersections to provide time to clear the railroad tracks of highway vehicles before a train arrives. This paper describes preemption performance measures developed in Indiana that use high resolution, real-time traffic signal event data, and a gate-down confirmation circuit at an active railroad crossing. These performance measures are used to quantitatively assess the synchronization of the track clearance phase with the railroad gate position. Performance measure plots from over 4,000 preemption events over six months are presented. The lessons learned from the assessment of these performance plots are described along with changes made to the test site during the study period. The paper concludes with recommendations for incorporating a highway-railroad synchronization performance measure using the start of railroad active warning time as a surrogate gate-down confirmation circuit.

Critical Logistics Support Enables Fast Track Construction for High Speed Rail

Paper and PowerPoint presentation format will describe process for much faster logistics and construction management of new high speed track construction and improvement of existing FRA track from FRA Class 4 to Class 5 and Class 6 standards on existing freight railway lines. This process involves an integration of the long materials supply chain together with rapid process state of the art construction machines. These machines have been used in both European and Chinese high speed construction projects. Huge gains in new track kilometers and miles per day have been made in the last decade on the machinery side of the equation. The authors will show several case studies. The critical key to these production rates has been in the integration of materials ordering and prepositioning. The economic advantage is that track time construction windows that delay other passing trains can be reduced at tremendous savings in service and operational costs to the operators already providing service in these new high speed corridors and construction zones. Examples and calculations are shown.

Augmentation of Level Crossing Safety Using Real-Time Video and Numerical Warning System

Official statistics showed that more than half of level crossing accidents in Taiwan were caused by intrusion of road users violating the right-of-way of the railroad. Thus it is critical that addition measures be developed to prevent or mitigate the seriousness of intrusion incidences even though many warning facilities are already in place. In this paper we propose to use real-time crossing cite image to provide train drivers with more vital information than alarm signals. In addition, we also take advantage of the radio link capacity to display numerical information of train distance on the fly to deter potential intrusion attempts. The result of this project can be used as reference design for the augmentation of level crossing safety of rail systems facing similar intrusion problems.

The Vulnerability Assessment Method of Railway Network

Vulnerability in the Railway system is, studied not only from the perspective of network topology characteristic but also as the problem of the level of service relative to structure, nature damage and traffic attribute. Also, emphasis is put on the function of the system rather than the physical network itself, although some of non-serviceability in the railway network is indeed caused by physical failures. The Vulnerability of railway network is thus a decisive factor not only in terms of connectivity, and serviceability, but also in terms of the transport system performance under dynamic process-traffic which should be acknowledged as an integral element within vulnerability assessment. The paper aims at investigating the most typical factors that affect the vulnerability. The vulnerability analysis must consider each factor separately, and, at the same time, as a whole. A method to measure the vulnerability is proposed. Furthermore, this assessment method is used to analyze the Chinese Railway Network (CRN).

Development of an Unattended Track Geometry Measurement System

Compliance with track standards and control of maintenance costs are critical aspects of the management of railroads. To facilitate this, track geometry measurement systems have evolved to allow monitoring of key track geometry parameters from moving trains. This paper describes how DeltaRail’s Trackline Two™ track geometry measurement system has been developed to overcome key technical shortcomings in existing systems. The resulting step change provides a cost-effective, robust, compact measurement system suitable for use on the broadest possible range of rail vehicles and networks, from a tram to a TGV. Extensive testing has demonstrated full compliance with appropriate standards. Significant improvements in reliability and repeatability of data have enabled DeltaRail to produce a modular system capable of sending data direct to value-adding analysis tools such as TrackMaster™ and VAMPIRE® so that track maintenance management can be optimized around train fleet and operational conditions. The system is easily operated in unattended mode allowing collection of track geometry data from in-service trains, increased frequency of data collection, and pointing the way for the track maintainers to realize significant value from integrated analysis and management options.

Rehabilitation of Railroad Bridges Using GFRP Composites

The use of glass fiber reinforced polymer (GFRP) composite materials to rehabilitate timber Railroad Bridge is investigated in this research. Two different rehabilitation methods were developed and implemented to strengthen timber stringers using GFRP. These methods are referred to as GFRP spray lay-up and vacuum bagging of GFRP wraps around timber members. Tests were conducted on four full scale (8″×16″×12″) timber stringers in the WVU-CFC laboratory under four point bending loads. These creosote treated timber stringers were loaded up to 20% of their ultimate loads to verify their properties. The stringers were then repaired using the above two rehabilitation methods and retested to failure. Strengthening the stringers with GFRP composites increased the shear moduli of the two stringers by 41% and 267%. Rehabilitation and load testing were carried out on an open-deck-timber railroad bridge built during early 1900’s on the South Branch Valley Railroad (SBVR) owned by the WVDOT in Moorefield, WV. Specifically, field rehabilitation involved repairing piles using GFRP composite wraps and phenolic formaldehyde adhesives. Using a 80-ton locomotive, static and dynamic tests were performed to determine the dynamic response of the substructure. Rehabilitated SBVR Bridge showed a 43% and 46% strain reduction in the piles and pile cap, respectively.

KENTRACK, a Performance-Based Layered Elastic Railway Trackbed Structural Design and Analysis Procedure: A Tutorial

KENTRACK is a layer elastic finite element based computer program that can be utilized for a performance-based structural design and analysis of railway trackbeds. Kentrack was initially developed to analyze traditional all-granular layered trackbeds and asphalt layered trackbeds. The versatility was recently expanded to analyze trackbeds containing a combination of granular and asphalt layers. The principle factor in the analysis is to limit vertical compressive stresses on the subgrade. In addition, it is possible to consider the fatigue lives of the various layers relative to the effects of wheel loads, tonnages, environmental conditions and other factors. The service lives of the individual components of the trackbed are predicted by damage analysis for various combinations of traffic, tonnages, subgrade support, component layer properties and thicknesses. The latest version, KENTRACK 3.0, is coded in C#.NET, a popular computer language for achieving accuracy and efficiency. The graphical user interface in the KENTRACK 3.0 provides a technique to analyze trackbeds as structures. It is possible with KENTRACK 3.0 to select trackbed layers and associated thicknesses to satisfy roadbed and trackbed performance requirements. In addition, it is possible to performance-rank different track sectional designs based on the relative importance of the particular track section and track type. The types of roadbed and trackbed configurations are selected to meet each of the various performance ranks. The various steps involved in the calculations are highlighted during the tutorial phase of a sample design calculations and analysis.

Design and Construction Technologies

Combining with the actual situation of China’s railway construction, this paper introduces the key technologies of design and construction of high-speed railway, such as the scheme optimization of subgrade, bridge and tunnel, technical standard, deformation control, advance geology forecast and settlement observation, etc. It also discusses the design and construction problems on the slab layout and interface of CRTS II slab track on bridge section, switch area, subgrade area and the transition with different track structures.