Hamed Pouryousef

Hybrid simulation approach for improving railway capacity and train schedules

Timetable management is one of the operational methodologies commonly applied in the highly structured European rail system to improve the capacity utilization while maintaining acceptable level of service (LOS) parameters; but their potential benefits to the less structured U.S. system have received little attention. The objective of this study was to investigate the use of timetable management features to analyze the trade-off between LOS parameters and capacity utilization in the U.S. The research applies a hybrid simulation approach, where output from RTC, a simulation tool developed in the U.S., was used as an input for timetable compression by RailSys, a simulation tool developed in Europe. 28 scenarios were developed in RailSys to identify a preferred scenario with reasonable LOS parameters while maintaining the capacity utilization under the recommended threshold, and the selected scenario of RailSys was then validated in RTC. The results of the study revealed that 10-min maximum allowed dwell time provided the best corridor capacity utilization. Also, the LOS parameters were significantly improved for total number of stops (55% reduction), total dwell times (80% reduction) and average dwell time (65% reduction); while the timetable duration was increased (capacity utilization was degraded) by 18% compared to the initial schedule.

Evaluating the Results and Features of Two Capacity Simulation Tools on the Shared-Use Corridors

The majority of passenger rail services in the United States (U.S.) operate on the shared-use corridors with freight rail. These types of operations tend to be challenging due to high heterogeneity, particularly in terms of reliability of service and capacity availability. The projected growth in demand for rail transportation is likely to exacerbate the situation. Similar to the U.S., the European passenger rail services are generally operated on shared-use corridors, but the infrastructure conditions and the operational priorities and patterns typically allow more reliable and higher speed passenger operations in comparison to the U.S. trains.Both continents use capacity and simulation software to analyze capacity allocations and operational limitations. However, the effects of the software selection haven’t been investigated. This research reviews two common simulation tools developed in the U.S. and Europe, Rail Traffic Controller (RTC) and Railsys, respectively. The paper reviews the structure and the main components of these two simulation tools. It will also present the outcomes of running RTC and Railsys through a given segment of shared-use track based on the same rolling stock, operation and signaling characteristics and analyze the similarities and differences between the outcomes of RTC and Railsys.© 2013 ASME

Sensitivity Analysis of Track Maintenance Strategies for the High Speed Rail (HSR) Services

Track Maintenance (TM) is one of the critical parts of rail operations and asset management. It has been estimated that about 25–35% of all operational costs are related to the track maintenance performance which can be typically classified as either corrective maintenance (CM) or preventive maintenance (PM). The first is a more reactive approach, where maintenance is conducted when inspections have revealed a need for action. The latter is a strategic approach that is mainly applied through maintenance planning. High Speed Rail (HSR) systems, especially on shared HSR corridors, can complicate track maintenance conditions due to the tight tolerances and precision, reliability and safety issues required by HSR. This paper evaluates strategic approaches for track maintenance planning along selected HSR corridors with either shared or dedicated operation pattern. The paper uses analytical and descriptive parameter tables to evaluate how sensitive a corridor is to changes in essential criteria for developing track maintenance strategies (TMS). These criteria may include: - HSR traffic conditions and operations regime; - TMS approach (or strategy) on current rail lines connected to the new HSR line; - Operation and Maintenance (O&M) structure of HSR management system. The descriptive parameter tables have been used by a specific PM modeling approach called preventive maintenance scheduling problem (PMSP). Before running PMSP model over a designated line, the respective parameters of the model should be calibrated and analyzed based on the line specifications. The descriptive parameter tables can be used during calibration procedure to assist in analyzing the sensitivity of model’s parameters and variables for the above mentioned criteria. This paper discusses and compares TMS approaches on three planned HSR corridors in Europe (Lisbon-Madrid HSR), Asia (Tehran-Isfahan HSR) and USA (California HSR). All three HSR rail corridors are under development, but each presents specific sensitivities to the given PM model’s parameters that can affect track maintenance strategic planning along these corridors. We concluded that TMS model calibration by these descriptive analytical tables can assist maintenance strategic planners in identifying different TMS approaches when dealing with maintenance contractors, HSR operators and public rail authorities.Copyright

The Role of Railroads in Multimodal Woody Biomass Transportation in Michigan

Minimizing transportation costs is essential in the forest products industry, as the relatively low value and high weight of the products causes transportation to account for exceptionally high portion of the overall cost. The forest products such as logs, chips, and residues (woody biomass) are one of the major business sources in Michigan especially in Upper Peninsula of Michigan. Currently, truck transportation is used for the great majority of the trips, but it is believed that a more cost-efficient transportation chain might be achieved through use of multimodal approach by trucks and rail and in some cases water transportation.This paper presents the three alternative transportation supply chain models for woody biomass transportation; 1) single mode, 2) multimodal and 3) intermediate storage. The paper uses data from three recent studies to describe the forest products transportation in the upper mid-west, including the typical distances for movements and the breakdown of cost elements for each alternative. It will discuss the potential benefits of increased use of rail as part of the transportation chain and address the perceived drawbacks and challenges caused by the shift. It will also present cost-gradient maps developed to highlight the capability of rail to expand the economical radius for obtaining feedstock and demonstrate how increasing fuel prices change the balance toward multimodal transportation. Finally, the paper will highlight the potential for gained efficiency in log truck operations through increased use of rail.Copyright