The continuing growth of population density in urban areas around the world has placed greater emphasis on the utilisation and development of underground space to meet the increasing demands of the city. Due to limited land space available in downtown areas, many cities in the world are also embarking on integration of major construction projects of metro infrastructure, commercial developments and residential estates, etc., to meet the growing demand of infrastructure In land-scarce Singapore, the development of a comprehensive and well-integrated public transport network is important to achieve a people-centric, world-class transport system. To enhance the connectivity of a rail network, interchange stations and underground linkways are constructed to connect the various lines so that transfers between mass rapid transit (MRT) lines can be seamless. Hence, it is becoming more challenging to construct a new MRT line in the vicinity of existing MRT lines without impacting the operations of existing MRT lines. The prime aim of this study is to present the ways to overcome the challenges in construction of secant bored piles (SBPs) above the existing underground MRT linkway (15 m below ground) and adjacent to the existing underground MRT East West Line station. The paper presents four different techniques applied to construct the SBP wall in the sandy soil since the conventional method of construction was not applicable to the site condition. The new techniques were successful as the SBP wall was constructed while keeping the vibrations and movement to the existing MRT structures within the allowable limits. From this venture, it can be concluded that it is possible to install SBPs in sandy soils without any significant impact on adjacent structures and construction timeline. The experience gained from this endeavour will be invaluable and can serve as lessons learnt for SBP works in the densely populated area and in the vicinity of existing sensitive structures which is increasingly becoming unavoidable.
The performance of Tyne and Wear Metro system in the UK is measured on a headway basis, and gaps in service that are 4 min or more in excess of scheduled gaps are investigated and the cause documented. The metro system has a number of infrastructure constraints including single-line sections, junctions and level crossings, all of which have to be taken account of when constructing the timetable, in order to avoid trains being held by the signalling system, causing delays. The objective of this study is to analyse delays less than 4 min, which are not investigated or attributed to a cause, known as sub-threshold delays. The purpose of the analysis is to identify regularly occurring issues which are due to the timetable, in order to recommend changes. Two different data sets were used. The first data set explored specific trains, areas and times of day where delays were highest. The second data set allowed us to drill down on each of those in greater detail by studying station departure times for each train. A number of options to resolve the issues identified during the analysis are proposed. Whilst the results are specific to the Tyne and Wear Metro system, the methodology is suitable for use by other urban rail transit systems. The study identified several areas of future work including resolving data recording issues, carrying out further investigation of trains at peak times in particular scenarios, and automating the analysis through the use of other software.
While high-speed train systems have accelerated mobility in China during the twenty-first century, the train systems of normal speed have gradually been replaced and abandoned, resulting in a "rust belt" in some Chinese cities. The reuse of abandoned railways provides a way to rebuild urban public transit based on the traditional tracks, and is also a way to transform towards urban regeneration of the surrounding neighborhood. Previous studies discussed the possibilities of three perspectives of reusing the abandoned rails: as a new transportation route, as a place for tourism and commerce and as a green corridor for the public. As a case study, this paper selects Zhangjiakou City, which is the terminal of the first railway routes built by Chinese, and explores methods of transformation from rail to urban rail transit. Under the background of the Beijing Winter Olympics of 2022 being partly held in Zhangjiakou City, the old North station and a 10-km rail between the North and South Station have been abandoned since 2014. This paper suggests conversion of the railway into an urban tram to meet the increasing commuter flow between the old and new city center. Additionally, transformation of the abandoned railway located in the city center will also trigger the urban space regeneration by increasing more urban functions and promoting urban public space. This research might shed light on other cities with similar transforming transportation facilities by analyzing the reuse possibilities of Beijing-Zhangjiakou Railway in Zhangjiakou City.
The present study investigates the determinants of vehicle dwell time at stations in urban light rail networks. Using data collected from an on-board automatic passenger counting system of the tramway network of the French city of Nantes over a long period, the study performs graphical and statistical analyses enabling the identification of cause-and-effect relationships of a number of attributes on the dwell time and its reliability. The results confirm the significance of the boarding and alighting passenger volumes, as well as of the on-board passenger loading, on the dwell time. Additional effects on dwell time are found from the vehicle type (low- or high-floor), the time of day (peak, off-peak, inter-peak) and the location of the station (city centre, proximity to points of interest). Also, it is found that operations are not symmetrical, and dwell times tend to be higher in one direction than the other of the same line. Finally, the results suggest that dwell time reliability is lower for stations located further from the starting terminal, or for stations located in the city centre.
Condition monitoring is used as a tool for maintenance management and function as input to decision support. Thus the key parameters in preventing severe damage to railway assets can be determined by automatic real-time monitoring. The technique of radio-frequency identification (RFID) is increasingly applied for the automatic real-time monitoring and control of railway assets, which employs radio waves without the use of physical contact. In this work, a 243-km2 area of Kuala Lumpur was selected. Because of its large size, determining the locations in which to install the RFID readers for monitoring the bogie components in the Kuala Lumpur railway system is a very complex task. The task involved three challenges: first, finding an optimal evolutionary method for railway network planning in order to deploy the RFID system in a large-area; second, identifying the large area that involved functional features; third, determining which station or stations should be given priority in applying the RFID system to achieve the most effective monitoring of the trains. The first challenge was solved by using a gradient-base cuckoo search algorithm for RFID system deployment. The second challenge was solved by determining all necessary information using geographic information system (GIS) resources. Because of the huge volume of data collected from GIS, it was found that the best method for eliminating data was to develop a new clustering model to separate the useful from the unuseful data and to identify the most suitable stations. Finally, the data set was reduced by developing a specific filter, and the information collected was tested by an analytic hierarchy process as a technique to determine the best stations for system monitoring and control. The results showed the success of the proposed method in solving the significant challenge of large-scale area conditions correlated with multi-objective RFID functions. The method provides high reliability in working with complex and dynamic data.