Environmental Performance of the Rail Transport System in a Life-Cycle Perspective : - The Importance of Service Life and Reuse in Sweden
The focus in environmental management has during the last decades in many cases shifted to include all the phases in a product’s (or a service’s) life – the life-cycle perspective. The transport system has a large environmental pressure on the environment. Train traffic is habitually regarded as an environmentally preferable mean of transport, mainly depending on that trains often are driven by electricity. This view is also true when the operation phase alone is considered; at least if the electricity derives from renewable sources. In a life-cycle perspective the advantages of this mean of transport get less apparent. The extraction of the raw materials requires plenty of energy, energy which often is produced by fossil fuels. A dominating part of the material-related energy requirements in the railway infrastructure can be referred to a few materials. The main part of these materials can be found in a few products; rails, railway ties, ballast materials, cables and the contact wire system. It is here that the effort to reduce the environmental impact of the railway infrastructure should lie to become most efficient. The aim of the thesis is to investigate how the environmental pressure is affected by the service lives, i.e. the technical durability as well as the durability in practise, of the most energy-intense railway products, as well as reuse of them. The objective is to map estimated service lives and reuse in order to create scenarios representing the present state of how the products are used and reused in Sweden. The scenarios are used in order to analyse the importance of focusing on service lives and reuse when reducing environmental pressure. The objective is also to find out which possibilities and hindrances there are to increase the service lives and the reuse of the products.
To investigate the environmental pressure of the railway infrastructure, embodied energy is used as indicator. Embodied energy represents the energy needed to produce a product, from extracting the materials to the production phase. The present state concerning service lives and reuse of the studied products are mapped through interviews with employees at Banverket and at VTI. The empirical material is analysed and scenarios are created in order to evaluate the environmental importance of service lives and reuse. Organizational issues concerning service lives and reuse are also investigated.
The present state service lives varies between 25 and 100 years for the realistic scenarios for all the products. The estimated service lives varies between 25 and 100 years for the new technology scenarios. When it comes to the best-case scenarios the estimated service lives varies between 60 and 120 years, depending on railway product. The only products reused today are rails and railway ties. There are considerable improvements to be made by increasing service lives, and this pertains to all the studied products. The reductions in embodied energy per year go up to 75 % if the New-Technology Scenario is applied and to 33 % if the Realistic Scenarios are applied. If the Low Realistic Scenarios are applied the reductions goes up to 50 %. A great improvement potential exist for all the products if the New-Technology Scenarios are applied. The products where the main improvement potential when it comes to the Realistic and the Low Realistic Scenarios exist are the macadam-ballast, the cables, the rails and the railway ties. If the New-Technology Scenarios are applied for all the products the total improvement span is as much as 69 % altogether. If the Low Realistic Scenario instead is applied, the improvement span is calculated to 38-39 % (depending on the exchange level of macadam-ballast). If the Realistic Scenario is applied, the improvement span is calculated to 23 % and if the Best-Case Scenario is applied the span is calculated to 7 %, depending on that the most energy efficient strategy is to reuse the products possible to reuse. The main part of this improvement potential derives from the rails and the railway ties.
In reducing the environmental pressure it is important to make use of the products as much as possible, i.e. to reuse them and use them as long as possible. If rails and railway ties are reused and made use of during their entire service life, all energy invested in the products is made use of. The most environmental sound alternative is to reuse the products which are reusable and to use these products as long as they last. This gives a need for embodied energy of 16 GJ/yr and km for the railway ties and 38 GJ/yr for the rails on the mainline track. The energy allocated to the tracks where the products are reused is calculated to 3 GJ/yr and km for the railway ties and to 7 GJ/yr and km for the rails. Actions of maintenance prolong the durability of the products, e.g. by increasing the stability in the embankment and hence reduce the wearing. The administration of the used material is the main problem in order to create a well-functioning reuse of railway articles. This includes transports, storage and documentation of products. Tradition and routines also stand in the way of creating a sustainable reuse of these products.
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