A Model for Optimizing Railway Alignment Considering Bridge Costs, Tunnel Costs, and Transition Curves

Abstract

Owing to wide-ranging searches (there are various alignments between two points) as well as complex and nonlinear cost functions and a variety of geometric constraints, the problem of optimal railway alignment is classified as a complex problem. Thus, choosing an alignment between two points is usually done based on a limited number of alignments designed by experts. In recent years, the study of railway alignment optimization has shown the importance of optimization and the introduction of various algorithms and their usefulness in solving different problems. It is expected that applying meta-heuristic optimization algorithms such as methods based on swarm intelligence can lead to better alignments. In this study, we tried to modify models based on previous studies in order to design and develop a model based on a single framework to provide three-dimensional optimization of alignments applicable in the real world. To obtain this, the particle swarm algorithm is used and a geographic information system is incorporated as a means of search in three-dimensional space. In particular, the cost function used in previous studies considering the costs related to structures (bridges and tunnels) are improved regarding hydraulic structure alignments. Furthermore, the transition curve of horizontal alignment and slope restrictions of curves are considered in this project by using the penalty function in order to obtain the most practical results possible. Finally, this study examines three problems for which the results are acceptable in cases of railway alignment geometry and its application in the real world.

Sampling‐based modified ant colony optimization method for high‐speed rail alignment development

“…Mountain railway alignment design Li et al (2016Li et al ( , 2017, Zhang et al (2018Zhang et al ( , 2020, Pu et al (2019), Song et al (2021) Segment length and other geometric design criteria vary with change in railway modes; clothoid spiral curves are not suitable for higher design speeds of HSR Urban railway alignment design Jha (2011, 2012), Lai (2012), Lai and Schonfeld (2016), Ghoreishi et al (2019) High-speed rail alignment design Costa et al (2013Costa et al ( , 2016, Song et al (2022) Simplified piece-wise linear alignment design considered in earlier studies; clothoid spiral curves are not suitable for HSR higher design speed higher than180 km/h impact assessment. Multiple geometric design constraints based on HSR guidelines are checked during the alignment development process.…”

“…(2022) improved upon this by considering circular and transition curves in the HSR alignment design. Railway alignment development algorithms for urban rail (Ghoreishi et al., 2019; Lai & Schonfeld, 2016) and mountain rail (Pu et al., 2019; Song et al., 2021; Zhang et al., 2018, 2020) had considered circular and transition curves. However, the geometric design details of urban and mountain rails are different from HSR.…”

Bilevel Optimization of Intercity Railway Alignment

“…The proposed eight kinds of mutation and crossover operators are also hard to handle (9). A customized particle swarm optimization was also developed as an alternative for HAO (16), which has been upgraded to optimize railway alignments (17).…”

Systemic Efficiency: A Key Consideration in the Design of New Dedicated Rail Freight Projects in Southern Africa

“…The macro-alignment of a railway network consists of its horizontal and vertical alignments [18]. The horizontal alignment consists of curves and tangent (straight) sections of line, and represents the linear characteristics of the alignment in respect of track length capacity.…”