Technical-Economical Evaluation of Chain Vertical Alignment in Underground Urban Subways: The Case of Qom Subway, Line A
Ali Abdi Kordani and Amirarsalan Mehrara Molan
International Journal of Railway, vol. 7, no. 2, pp.35-39, 2014
Abstract : Urban subways are one of the main parts of urban transportation networks in every city that always requires much attention
in order to improve its efficiency in aspects of safety, reliability speed and costs. As the viewpoint of costs, an accurate
design, especially design of vertical alignment, can have a dominant role to reduce the costs of urban railway
projects. This paper seeks to evaluate the advantages and disadvantages of designing chain vertical alignment for urban
subways in compare to flat vertical alignment. To achieve this goal, line A of Qom subway in Iran was selected as a case
study in this research. Five parameters considered in the technical-economical evaluation: (1) energy consumption, (2)
rolling stock, (3) operation, (4) civil works and geotechnical and (5) hydrological, drainage and pumping. According to
the results, a power saving of about 40% have been estimated in the chain vertical alignment for the train without regenerative
braking in compare with the flat vertical alignment, although the power saving was calculated less than 10% for
the train with regenerative braking. Finally it was found that due to the modern rolling stock technology, the chain vertical
alignment represents fewer advantages in compare to the past years.
Keyword : Urban underground subway, Chain vertical alignment, Power supply saving, Construction costs, Technicaleconomical |