Alignment Optimization in Rail Transit

Authors: Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Book Series : Lecture Notes in Intelligent Transportation and Infrastructure

Part of: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

Table of Contents

About this book

This book deals with alignment optimization models for planning rail transit. After a general introduction to the basics of alignment optimization theory, it presents different alignment optimization methods to deal with different situations. It shows how to set up a 3D GIS scene for alignment interaction design, including location calculation of an alignment, alignment expression in a 3D scene, and the spacial relations between geographic objects, horizontal alignment, and vertical alignment. Further, it presents methods for solving more complex alignment optimization models, and shows for each different rail transit situation, how to calculate investment, energy consumption, and environmental influence. All in all, this book offers an interesting and timely reading to both researchers and professionals in the field of optimization theory, transportation planning, and GIS.

Frontmatter

Chapter 1. Introduction

Abstract

Alignment design is an essential procedure in the design process of a rail transit project. It is valuable to study the optimization method of rail transit alignment and realize it through an interactive design system as the investment scale and environmental impacts are closely related to the alignment scheme. In Sect. 1.2, the development of the business interactive design systems of rail transit and highway alignments and the technique demand of alignment optimization system are analyzed. Afterward, we conduct a literature review about optimization models of rail transit and highway alignments from 1968 to 2023. Through the development analysis of alignment optimization models, we introduce some further study requirements of alignment optimization models and present the purpose and content of this book.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Chapter 2. Basic Alignment Optimization Models

Abstract

Civil engineers should strive to design reasonable parameters of civil structures following various codes, specifications, and requirements in pursuing better design schemes. In traditional procedures, designers could gradually obtain a good scheme through trial-and-error methods. However, there are always better alternatives than the current scheme generated by manual comparisons. Optimization theory, as a branch of mathematics, could be applied through computer programs to improve the defects of manual design. It aims to search for the best scheme determined by a series of variables satisfying some constraints. This chapter outlines the characteristics of optimization theory, puts forward the features and structures of alignment optimization models, proposes the idea of model solutions based on the differential evolution algorithm (DE), analyzes the limitations of the proposed alignment models, and proposes some improvement strategies.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Chapter 3. Alignment Interactive Design in a 3D Scene

Abstract

An alignment determines the distribution of stations, bridges, tunnels, and subgrades following some predefined codes. Alignment interactive design is the precondition for alignment optimization. When an engineer trying to design an alignment, the preparatory work is the data preparation and understanding of the geographical environment. Alignment interactive design is a design-evaluation-redesign process based on the geographical environment. Generally, there are three desired capabilities of a software program for alignment interactive design. Firstly, it can integrate multi-source data inside a three-dimensional (3D) scene, including terrain data and various feature data of geographical objects. Secondly, it not only supports the alignment interactive design in the traditional two-dimensional (2D) manner but also expresses the real spatial alignment and the related sketches of civil structures for intuitive analysis. Thirdly, it can calculate the quantities of civil work and other indexes supporting the automatic alignment evaluation. This chapter introduces how to make a program for alignment interactive design through osgEarth and Qt integration to realize the above operations.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Chapter 4. Single-Level Optimization of Metro Alignment with Single-Objective

Abstract

The metro system is the trunk of the transportation network in large cities. The most common construction method for metro projects is the shield method which makes the direct investment closely related to the length of horizontal alignment and the energy consumption of a train operation closely related to the slope composition of vertical alignment. This chapter introduces a double line optimization for the metro alignment in which both equality and inequality constraints are considered. To deal with the density obstacles in the geographical environment for horizontal alignment optimization, we propose three strategies, i.e. direct optimization, optimization with an existing seed, and optimization in successive two stages. Three practical cases are explained to verify the efficiency of the three strategies respectively. In the optimization of metro vertical alignment optimization, we analyze three operating modes i.e. coasting mode, cruising mode, and hybrid mode, and propose their corresponding optimization models. Afterward, the traction calculation of the metro train is explained in detail to realize the calculation of the objective functions. Nine cases are explained to verify the efficiency of the three optimization models of vertical alignment respectively.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Chapter 5. Bi-level Optimization with Single-Objective for Railway Alignment

Abstract

A railway alignment consists of a horizontal alignment and a vertical alignment. There is a strong coupling relation between the geographic environment, the horizontal alignment, and the vertical alignment if the terrain fluctuation is large or the horizontal features are complex. This chapter proposes a bi-level optimization model for railway alignment considering investment descent. The upper level is responsible for the horizontal alignment optimization, and the lower level is responsible for the vertical alignment optimization. A multi-stage optimization strategy including corridor scheme generation, initial scheme generation, and optimal scheme generation is suggested which not only upgrades the optimization efficiency but also confirms the suitable number of HPI and VPI gradually.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Chapter 6. Bi-level and Bi-objective Optimization of Railway Alignment in Ecologically Sensitive Area

Abstract

When a railway project passes through an ecologically sensitive area, the reasonable alignment scheme should not only save the investment but also protect the ecological environment. There are various special structure design and construction approaches in a railway project for ecological protection which can be impressed by cost items. However, it is inevitable to acquire some land for the permanent structures of bridge, subgrade, tunnel, and station, where the primitive vegetation and soil are destroyed or disturbed. This chapter proposes a bi-objective optimization model for railway alignment considering the descent of investment and ecological damage simultaneously. Firstly, the structure design and construction approaches for ecological protection are discussed. The principles to set the investment objective considering ecological protection are proposed; Secondly, the ecological objective function to evaluate the ecological damage is described. Thirdly, the bi-level and bi-objective Optimization model of railway alignment is proposed and a multi-objective optimization based on a DE algorithm and decomposition strategy is introduced to solve the optimization model. The case study shows that the suggested optimization model can generate a set of diverse horizontal alignments most of which are on a Pareto Front.

Dongying Yang, Honghui Wang, Sirong Yi, Qing He

Title: Alignment Optimization in Rail Transit
Authors: Dongying Yang
Honghui Wang
Sirong Yi
Qing He
Publisher: Springer Nature Switzerland
Electronic ISBN: 978-3-031-80561-5
Print ISBN: 978-3-031-80560-8
DOI: https://doi.org/10.1007/978-3-031-80561-5