Cut spikes have been used to hold rails directly to wood ties and thus provide lateral restraint to rails and maintain rail gage. For tightly curved and/or steeply graded wood tie tracks, particularly those undergoing heavy loads, elastic clips have been increasingly used to fasten rails securely to tie plates, which in turn are held down by cut spikes or lag screws to the crossties. However, several recent derailment accidents were attributed to the breakage of significant numbers of spikes used in association with the elastic fastening systems. A commonly observed failure mode is the development of fatigue cracking across spike surfaces located approximately 1.5 inches below the top surface of the tie. Previous Finite Element (FE) studies have shown that the presence of longitudinal force transmitted into the tie-spike interface is significant to accelerate wood damage and cause spike failure initiation as the strength of wood along the track longitudinal direction is weaker than the other directions. In the field, the magnitude of longitudinal load between a tie and fastener is very difficult to measure relying on the current sensor technology. A literature review conducted so far indicates that longitudinal-load-distribution related computational models are very limited. Therefore, the distribution mechanism of longitudinal load has not been well-established. To better understand how the longitudinal load is transferred from wheels to ties and fasteners, this paper developed an analytical model to investigate the longitudinal tie forces using the finite difference method. In this paper an analytical model is firstly introduced to calculate the longitudinal track response under a single static wheel load. The solution calculates diverse sets of responses such as: (1) rail axial displacements; (2) rail axial forces; (3) force distribution to the tie; and (4) tie forces. The effect of multiple axle loads from a train is then computed using superposition theory. To validate the model, a field test was performed at the Horseshoe Curve in Altoona, Pennsylvania to investigate longitudinal rail forces and longitudinal displacements of rail and ties under train passages. The model predictions were compared and validated with the test results. This model applies to all train types on various track layouts. Key factors, e.g. train braking versus train traction, fastener stiffness, etc., that have a significant effect on longitudinal force distributions are presented in the paper. The model estimates the longitudinal forces during uniform train braking and traction events, and shows that locomotives in traction lead to more significant longitudinal forces distributed to ties. The results indicate the longitudinal force was distributed over a large span (or influence zone) of over one hundred ties whereas the vertical tie load was only distributed over three to five ties. Within the influence zone of the longitudinal load, the vertical tie load ranged dramatically from maximum compressive forces (negative forces) to uplifting tensile forces (positive forces), indicating load configuration was very tie-dependent under a train passage. Significant longitudinal forces could be existing on uplifted ties. The results also show that larger longitudinal stiffness of fastener led to higher maximum forces distributed to ties and smaller influence zones.

The Federal Railroad Administration’s (FRA’s) Office of Research and Development has undertaken a multi-phase research program focused on the development and advancement of Autonomous Track Geometry Measurement Systems (ATGMS) and related technologies to improve rail safety by increasing the availability of track geometry data for safety and maintenance planning purposes. Benefits of widespread use of ATGMS technology include reduced life-cycle cost of inspection operations, minimized interference with revenue operations, and increased inspection frequencies. FRA’s Office of Research and Development ATGMS research program results have demonstrated that the paradigm of track inspection and maintenance practices, information management and, eventually, government regulations will change as a result of widespread use of ATGMS technology by the industry. A natural consequence of increased inspection frequencies associated with ATGMS is the large amount of actionable information produced. Therefore, changing existing maintenance practices to address a larger number of identified track issues across large geographic areas will be a challenge for the industry. In addition, managing ATGMS data and assessing the quality of this information in a timely manner will be challenging. This paper presents an overview of the FRA’s ATGMS research program with emphasis on its evolution from a proof-of-concept prototype to a fully operational measurement system. It presents the evolution of ATGMS technology over time including the development of a web-based application for data editing, management and quality assurance. Finally, it presents FRA’s vision for the future of the ATGMS technology.

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To improve detection of railroad track defects that cause derailments, the Federal Railroad Administration Office of Research and Development with joint cooperation of the Railroad industry developed the Gage Restraint Measurement System (GRMS). This system measures the track's ability to support gage widening forces and marks the locations at risk for derailment. This paper describes the GRMS design, calculated safety indices, and application for use in maintenance planning. .0 BACKGROUNDThe GRMS is a performance-based track strength evaluation system designed to improve railroad safety and maintenance efficiency. The system was developed under ajoint effort by the federal government and the railroad industry. The agencies involved included the Federal Railroad Administration's Office of Research and Development, The Volpe National Transportation Systems Center, with the help of the American Railway Engineering Association and supporting contractors. Several railroads and private organizations contributed to the development by supplying equipment, personnel and track usage. ENSCO Inc., the cunent FRA instrumentation contractor, operates and maintains the prototype system. The GRMS has surveyed over 14,000 miles and is currently being used by several Class 1 and Short Line railroads to evaluate track gage strength under a cooperative cost-sharing anangement with the FRA.Since railroads were first used to move heavy equipment, maintaining the established distance between the rails (gage) has been a problem. The track gage is maintained by ties and fasteners. Ties are typically made of wood, concrete, or steel and perform three major functions. They hold the rails at the correct gage, distribute the loads applied by the train to the track foundation, and anchor the track against movement. The fasteners attach the ties to the rail and are typically cut spikes, screw spikes, or some type of spring clip. When the rail holding capacity of the ties and fasteners is exceeded by the forces generated by the train as it travels, the rails separate 174/SPIE Vol. 2458 O-8194-1811-0195/$6.OO Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms Under this program two prototype devices were developed that provide quantitative measurements of rail restraint capacity: the Gage Restraint Measurement System (GRMS) and the Lightweight Track Loading Fixture (LTLF). Both of these devices physically measure the rail SPIE Vol. 2458 / 17S Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms

Gaming journalism began its existence under attack from the rest of the journalistic field and from U.S. culture as a result of the audience to whom they appealed: young, diverse, progressive. This study argues that early gaming magazines (n=150) repaired the gaming paradigm during the development of gaming’s mainstream acceptance from 1991-1995 by challenging stereotypes of gamers: imagining their audience as diverse, social and mature.