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In order for a railroad to function effectively all aspects of the system should be maintained in good working order. Locomotives and rolling stock regularly move through areas where they can be inspected and maintained. However track does not move, so inspectors must traverse the line either on foot or in a rail mounted vehicle and maintenance crews must be sent to specific locations to make track repairs, which may not always happen before a service disruption. A track failure, due to either exceeding some industry or governmental specification or an acute failure, such as a rail break, can result in costly delays or even derailments with significant consequences. To help avoid such failures, it is beneficial for a railroad to be able to predict when and where failures might occur and then evaluate the relative costs and benefits of performing maintenance activities to ensure that the most cost effective actions are taken. A model is being developed to assist in the process of scheduling and directing track maintenance work. The model consists of three primary modules: an integrated track quality and degradation module, a maintenance activity selection module, and a scheduling optimization module. By taking into account a wide range of costs and benefits, the model can help railroad infrastructure managers better account for risk and indirect costs such as track time, as well as account for the criticality of certain types of imminent failures. This paper will describe the inputs and outputs for the model, as well as detailing the concepts associated with each of the model components.

Because railroad crossties are the second most valuable railroad asset, it is critical that they be maintained and managed in a cost-effective manner. The direct expenses of track maintenance cost railroads billions of dollars each year, and additional millions are spent on recovery from track-caused derailments. Train delay costs further increase the con sequences of unplanned track outages. Additionally, maintenance activities often result in traffic disruptions and congestion that can propagate throughout the rail network; this effect is a concern especially on higher-density lines that are vulnerable to cascading train delay and longer postincident recovery times. Compared with timber crossties, concrete crossties offer several potential benefits but also have a greater initial cost. Economic analysis can show instances in which extra capital investment in premium components is justified. Such analysis can also aid in planning general tie maintenance by balancing the costs of added maintenance with the associated benefit of reduced accident risk. This paper presents a model for evaluating the life-cycle economics of tie types by comparing concrete and timber crossties. A sensitivity analysis demonstrates how various inputs affect the cost comparison between timber and concrete ties.North American railroads spend billions of dollars each year on track maintenance, and crossties are one of the largest expenditures (1). Hence crosstie investments should be made on the basis of sound economics and maintenance performed in the most cost-effective manner. Track maintenance strategies differ in how frequently various components are renewed. In all cases, there is a wide range of associated costs that vary depending on operating conditions and that affect which alternative is the most cost-effective.For an accurate assessment of the cost-effectiveness of a maintenance procedure, the initial direct cost of labor and materials cannot be considered in isolation. Previous research discussed life-cycle costing (LCC) for track maintenance and construction (2-6). However, initial and recurring direct costs of labor and materials are not the only costs that should be considered. In a practical working railroad environment, it is difficult to perform all required maintenance without delaying train operations. Transportation and engineering departments frequently compete for track time. Delay costs related to track maintenance may be incurred by trains using the line undergoing maintenance but may also affect other parts of the network. Traffic density on North American railroads is expected to increase, exacerbating the delay associated with maintenance (7). If the overall impacts and costs of maintenance-caused train delay are not fully accounted for, suboptimal decisions regarding infrastructure investment and maintenance strategies may result. Specific to the comparison of concrete and timber ties, a frequently cited economic analysis of North American crossties states that its analysis methods do not adequately account fo...

To improve the personal mobility, safety, and environmental impact of passenger travel and to strengthen regional and national economies, planners, governments, and transportation companies throughout the world have been building high-speed rail (HSR) systems for more than half a century. Although many early systems were principally government projects, public–private partnerships are increasingly being used to design, build, operate, and maintain these HSR networks. However, engaging the private sector requires a clear understanding of the potential profit-ability of such a system. A key question affecting this understanding is the configuration of the line in terms of its length, number and location of stations, and ultimate alignment. A computer model was developed; it used station, route, and system data to determine the most profitable routes based on the proposed stations. In addition, a sensitivity analysis was conducted to determine which variables had the greatest impact on the costs and returns of an HSR route. The sensitivity analysis led to the division of the design variables into three categories based on their impact on profitability. Variables that were found to have a major influence were project concession period, ridership, fare, annual fare increase, train set availability, cost of building on a viaduct, and land value increase. Categorizing the design variables allows the model to be used more efficiently in a multiphase approach that reduces the time and resources required to assess potential HSR lines.

Broken rails are the most common cause of severe freight-train derailments on American railroads. Reducing the occurrence of broken-rail-caused derailments is an important safety objective for the railroad industry. The current practice is to periodically inspect rails using non-destructive technologies such as ultrasonic inspection. Determining the optimal rail defect inspection frequency is a critical decision in railway infrastructure management. There is a seasonal variation in the occurrence of broken rails that result in train derailments. This paper quantifies the effect of this seasonal variation on the risk-based optimization of rail inspection frequency. This research can be incorporated into a larger framework of broken rail risk management to improve railroad transportation safety.