Development of life cycle cost model and analyses for railway switches and crossings
Abstract: Infrastructure managers need to have a safe and available infrastructure, so that train operators can deliver a transport product at an affordable price. In the future, as traffic volume increases, higher utilisation of the existing capacity, less time for maintenance and fewer unplanned interruptions will be critical for meeting the ever increasing need of transport capacity. Improved performance and added capacity on the existing track can be achieved by optimising the operation and maintenance of infrastructure systems. In general, RAMS (Reliability, Availability and Maintainability and Safety) and LCC (Life cycle cost)-analyses are used as tools to optimize the performance of infrastructure and make it economically viable. RAMS analysis is used to establish the need of maintenance by analysing corrective and preventive maintenance data. LCC is a method of highlighting the cost for investment, operation, maintenance and unplanned interruptions throughout an asset's life cycle. Switches and crossings (S&Cs) are one of the major subsystems in the superstructure of the railway. The major function of an S&C is to allow trains to shift from one track to another track in a safe way. To enable this, an S&C consists of movable and fixed mechanical parts, as well as signalling and electrical systems. Each of these systems has a need for maintenance and is susceptible to failures which ultimately lead to train disturbances. The investment costs for new S&Cs are high and the technical lifespan is often very long (over 40 years). Therefore, the maintenance cost is considerable. If the S&C is causing many train interruptions, the cost for train delays is also an important factor for consideration. During the course of this research study, reliability and maintainability characteristics of switches and crossings are analysed using real data from Banverket. In addition, an LCC model is developed using information from Banverket. By applying this model, correct maintenance and investment decisions can be made. Some parts of the Research work have been performed within the European Framework of FP 6 IP Project INNOTRACK with a goal of reducing the LCC of infrastructure by 30 %. This research study confirms that the infrastructure managers have enough data to apply the LCC models for the S&Cs. The model developed can be used to evaluate new S&C designs and to take decisions regarding alternatives for S&C specification to be used under different traffic situations. Also the issue of decisions regarding renewal versus extended life through maintenance is highlighted by use of the LCC model.
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