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This report provides an outline of why railway infrastructure development is an important part of urban development and the multidisciplinary nature of its design and construction process (‘Engineering the Railway Industry,’). This report also includes an overview of a life cycle assessment of railway infrastructure, focusing specifically on the steel rail component of the track bed.
The life cycle assessment does not provide numerical data showing the environmental impact the component has during its lifetime, but rather an assessment of what the sources of environmental impact are. It was found that the parts of the steel rails life cycle with the greatest environmental cost are the construction and renewal processes, as well as the manufacture of the steel rails from raw components (Kiani, Ceney, & Parry, 2008). The sustainability of the steel rails life cycle is achieved by the relatively long lifetime of the steel rails, requiring them to only be installed and dismantled every 20-30 years. Another important sustainability strategy is the recycling of old steel rails, allowing up to 85% of the old steel rails to be remade and used again (Kiani et al., 2008).
The multidisciplinary nature of the development of the railway track was evident in the need for the professional knowledge and cooperation of engineers of many disciplines – primarily electrical, mechanical, civil, and computer to successfully complete such a large project. These engineers are not only in charge of the technical aspects of design and construction, but they must also be able to manage and oversee the construction of their designed components (United States Department of Labour, 2019a, 2019b, 2019c, 2019d).
Introduction:
Railway infrastructure is an integral part of urban development. Freight railways decrease both the cost and environmental impact of transporting commodities (Australian Railway Association, 2017), while passenger railways can support the development of new real estate land. Passenger railways are becoming an increasingly essential mode of transport as CBDs continue to develop and apartment and townhouse living become more commonplace (Australian Government, 2017), making it an essential part of urbanization. Most importantly, both freight and passenger railways can reduce road congestion and carbon emissions and support the growth of the nation as a whole, helping improve employment, wages, and GDP (Australian Railway Association, 2017).
The design, construction, and operation of rail transport systems fall under the term railway engineering. Railway engineering is a multidisciplinary line of engineering, encompassing the disciplines of civil engineering, mechanical engineering, electrical engineering, and computer engineering (‘Engineering the Railway Industry,’).
Life Cycle Assessment:
A life cycle assessment is a framework used to quantify the environmental impact and evaluate the sustainability of a product during its life span, from its manufacture, transport, maintenance, and ultimately disposal (Dowling, 2016). An overview of the life cycle assessment of a ballasted railway track bed will be explored, with a focus on the steel rail component of the ballasted railway track bed.
The most common type of railway track is the ballasted track, which is composed of steel rails with rubber rail support pads on re-enforced concrete (Kiani et al., 2008), all of which are supported and held in place by a layer of granular material known as ballast, typically made from coarse stone and gravel (Bressi, Apos, Angelo, Santos, & Giunta, 2018).
This life cycle assessment will examine the environmental impact of the manufacture, transport, construction, maintenance, and the end of life processes of the steel rails life cycle, as shown below in figure 1. Figure 1 (Kiani et al., 2008)
The manufacture of steel rails from raw materials also has a significant environmental cost (Kiani et al., 2008). The environmental impact of manufacturing the steel rails includes not only the consumption of large amounts of electricity and emission of carbon dioxide (Burchart-Korol, 2013) but also the fact that it consumes a non-renewable resource: iron. The effect of the latter is partially counteracted by the steels life cycle process, as 85% of old steel rails can be recycled and remade into new rails to be used again, significantly increasing the sustainability of rail track redevelopment (Kiani et al., 2008).
During the transportation phase of the steel rail life cycle, the main source of harm to the environment is air pollution, caused by the consumption of fuel by transportation vehicles. The exact environmental impact of transportation is difficult to determine as it is dependent on the distance between the development site and the manufacturer (Kiani et al., 2008).
The construction phase of the rail tracks involves using rail laying machines to install the steel rails. The main environmental impact here is due to the carbon emissions of the machines when in use. To lay a single kilometer of steel rail would require 185 liters of diesel fuel and take 37 hours to complete (Kiani et al., 2008).
Steel rails generally have a life expectancy of 20 years but can last up to 30 years. During this 20-year period, there is typically no need for any steel rail maintenance, they are however removed and replaced at the end of their lifetime (Kiani et al., 2008). The environmental impact of replacing the steel rails is approximately twice that of when it was installed, with the main source of harm being carbon emissions from machinery. 85% of used steel rails can be recycled and remade into new steel rails, directly reducing the energy used during manufacture (Kiani et al., 2008). Scrap metal from the steel rails can also be used to make other steel items, decreasing the environmental cost of manufacturing other items (‘Uses for Recycled Scrap Metal,’ 2015). This is the most important step in achieving sustainable redevelopment of rail infrastructure as it significantly decreases the environmental cost of manufacturing the rails and helps to reduce the depletion of iron sources.
Further research has been conducted to improve the sustainability of railway infrastructure redevelopment, for example, research into using different materials for the construction of the railway track to improve the lifetime of components, reducing the frequency and in turn environmental cost of maintenance and renewal, while also being economically viable (Indraratna, Ngo, & Rujikiatkamjorn, 2017). More specifically, research has been done with the aim of finding an alternative foundation bed material to the traditional ballasted track (Giunta, Bressi, Apos, & Angelo, 2018). While the ballasted track is highly durable and relatively quiet (Yi, 2017), the degradation of the track shape is a common issue due to the settlement of the loose ballast which causes the geometry of the track to change, resulting in the need for periodic examinations and maintenance (Bressi et al., 2018). New research attempts to find a solution to remove the need for such frequent maintenance, reducing the number of resources consumed during the life cycle of the rail track. The development of railway infrastructure also helps indirectly improve energy sustainability and reduce carbon emissions by providing a cleaner alternative mode of transport for people and for freight (Australian Railway Association, 2017).
Role of Civil engineers:
Civil engineers are the most involved in the development process of the rail track. Civil engineers must plan where and how the rail infrastructure will be constructed: considering the accessibility of the railway, the stability and strength of the foundations, possible environmental hazards, and the appropriate materials required to construct the railway (Australian Bureau of Statistics, 2016). They also design the geometric shape of the railroad, as to ensure the smooth and safe travel of the train. These tasks are not completed by a single civil engineer but rather by many civil engineers of different sub-disciplines. For example, the surveying of the foundations to ensure they can support the planned infrastructure would be completed by a geotechnical engineer, a sub-discipline of civil engineering specializing in the study of foundations that support structures (Australian Bureau of Statistics, 2016). While the design, construction, and operation of the railway itself would fall under the job of a construction engineer, a sub-discipline of civil engineering that specializes in the development of large infrastructure. And the design of structures such as bridges and tunnels that the railway passes through would be completed by structural engineers, engineers that are trained in the design of safe and stable structures (Australian Bureau of Statistics, 2016). Civil engineers are also heavily involved in the construction, maintenance, and dismantling phases of the railway. They plan, organize and manage the entire project, often traveling on-site, to ensure that the project is completed on time, within budget, and most importantly, safely (United States Department of Labour, 2019a). To this end, civil engineers must be able to plan efficiently to comply with time constraints, be able to obtain and estimate project costs to stay within budget, and create comprehensive risk assessment and risk management plans (United States Department of Labour, 2019a).
Conclusion:
Railway infrastructure is an essential part of the framework of urban development that helps connect people and cities together (Australian Government, 2017). The sustainability of the steel rails life cycle is achieved by recycling most of the old rails for the same purpose and by requiring little to no maintenance for the steel rails during their relatively long lifespan (Kiani et al., 2008). The design and construction of a railway track require the expertise and collaboration of engineers of many different specializations. Civil engineers must not only have a comprehensive knowledge of their specialized field but also be able to work both as a part of a team and as a leader. Civil engineers must have the skills to work well as a part of a team when designing the different parts of the railway infrastructure with other engineers. They also must be an effective leader when overseeing the development of this infrastructure, requiring them to possess leadership, planning, and time management skills (United States Department of Labour, 2019a, 2019b, 2019c, 2019d).
References:
- Australian Bureau of Statistics. (2016). Unit Group 2332 Civil Engineering Professionals. https://www.abs.gov.au/ausstats/abs@.nsf/Latestproducts/FEC9451D12A0D9B9CA2575DF002DA5EA?opendocument
- Australian Government. (2017). The National Rail Program: Investing in rail networks for our cities and regions. Retrieved from https://investment.infrastructure.gov.au/files/national_rail_program/national_rail_program_booklet.pdf.
- Australian Railway Association. (2017). A Rail Industry Plan for the Benefit of Australia. Retrieved from https://ara.net.au/sites/default/files/National%20Rail%20Industry%20Plan_full%20report.pdf
- Bressi, S., Apos, Angelo, G., Santos, J., & Giunta, M. (2018). Environmental performance analysis of bitumen stabilized ballast for railway track-bed using life-cycle assessment. Construction and Building Materials, 188, 1050-1064. doi:10.1016/j.conbuildmat.2018.08.175
- Burchart-Korol, D. (2013). Life cycle assessment of steel production in Poland: a case study. Journal of Cleaner Production, 54, 235-243. doi:10.1016/j.jclepro.2013.04.031
- Dowling, D. (2016). Engineering your future: an Australasian guide (Third edition. ed.). Milton, Qld: Wiley.
- Engineering the Railway Industry. Retrieved from https://www.applydirect.com.au/Blog/engineering-the-railway-industry
- Giunta, M., Bressi, S., Apos, & Angelo, G. (2018). Life cycle cost assessment of bitumen stabilized ballast: A novel maintenance strategy for railway track-bed. Construction and Building Materials, 172, 751-759. doi:10.1016/j.conbuildmat.2018.04.020
- Indraratna, B., Ngo, N. T., & Rujikiatkamjorn, C. (2017). Improved Performance of Ballasted Rail Tracks Using Plastics and Rubber Inclusions. In Procedia Engineering (Vol. 189, pp. 207-214): Elsevier Ltd.
- Kiani, M., Ceney, H., & Parry, T. (2008). Environmental life-cycle assessment of railway track beds. Proceedings of The Institution of Civil Engineers-engineering Sustainability – PROC INST CIV ENG-ENG SUSTAIN, 161, 135-142. doi:10.1680/ensu.2008.161.2.135
- United States Department of Labour. (2019a). Occupational Outlook Handbook, Civil Engineers. from Bureau of Labor Statistics, U.S. Department of Labor https://www.bls.gov/ooh/architecture-and-engineering/civil-engineers.htm
- United States Department of Labour. (2019b). Occupational Outlook Handbook, Computer Hardware Engineers. Retrieved from https://www.bls.gov/ooh/architecture-and-engineering/mobile/computer-hardware-engineers.htm
- United States Department of Labour. (2019c). Occupational Outlook Handbook, Electrical and Electronics Engineers. Retrieved from https://www.bls.gov/ooh/architecture-and-engineering/electrical-and-electronics-engineers.htm
- United States Department of Labour. (2019d). Occupational Outlook Handbook, Mechanical Engineers. Retrieved from https://www.bls.gov/ooh/architecture-and-engineering/mechanical-engineers.htm
- Uses for Recycled Scrap Metal. (2015). Retrieved from http://www.tucsoniron.com/uses-for-recycled-scrap-metal
- Yi, S. (2017). Dynamic Analysis of High-Speed Railway Alignment: Theory and Practice. San Diego: Elsevier Science & Technology.
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