GIS-based multi-criteria railway design with spatial environmental considerations

Abstract

Railway design is complex and closely linked to environmental concerns. To solve this problem, a two-stage method considering three categories of environmental factors (topography, ecology and geology) is proposed and demonstrated by being applied to a real-world case in China. The first stage focuses on environmental impact assessment. An elevation accessibility map is generated by determining railway spatially-reachable ranges. Then, the three categories of environmental factors are divided into 12 sub-factors and their spatial relations with railways are analyzed using a GIS. After that, an environmental suitability map is produced by combining the influences of these sub-factors with a multi-criteria analytical hierarchy process. The second stage focuses on automated railway design. The study area is first narrowed based on the two maps to determine feasible search spaces. Then, a distance transform algorithm is customized to search for railway alignments. During the search, a multi-criteria tournament decision method is integrated to optimize alignment solutions. Lastly, the application results of our two-stage method are analyzed. The outcomes reveal that the two environment-related maps provide effective descriptions of the study area. Through comparisons between the computer-generated railway and the best alternative produced by experienced designers, improvements of our method are also discussed.