Beijing-Tianjin Intercity High-speed Railway Research Articles

Synchronizing Last Trains of Urban Rail Transit System to Better Serve Passengers from Late Night Trains of High-Speed Railway Lines

Synchronizing last trains of Urban Rail Transit (URT) system is important for passenger transportation, especially for travelers from other modes, such as high-speed railway (HSR) trains in late night, to reach their destinations. This paper develops a bi-objective mixed-integer linear programming model for the problem of Last-Train Timetable Synchronization (LTTS) of URT system in late night hours. The bi-objective optimization model maximizes the number of passengers who can arrive at their destinations successfully, and minimizes the total operation ending time for last trains of URT system. This model can deliver both a last-train transfer scheme solution (i.e. which transfer connections to keep at which stations) and a last-train timetable of URT system (i.e. arrival and departure times for last trains at stations) at the same time. Transfer walking time is considered different for passengers, and suggestions for passengers to adopt certain transfer connections are dynamically dependent on the last-train timetable and passenger assignment. The Epsilon-constraint method is used to find the Pareto optimal solutions for the proposed bi-objective model. Numerical tests based on a sample network demonstrate the validity of the model on solving the LTTS problem. To evaluate the effectiveness and efficiency of the bi-objective model in practice, real-world experiments are conducted based on Beijing-Shanghai high-speed railway (HSR-BS) line, Beijing-Tianjin inter-city high-speed railway (HSR-BT) line and Beijing urban rail transit (URT) system. We also present a set of experiments to evaluate the benefits of considering different Transfer Walking Time (TWT) of passengers in the model, compared to models with constant and identical TWT for all passengers.

Numerical analysis to determine the impact of land subsidence on high-speed railway routes in Beijing, China

Abstract. More than 10 high-speed railway routes with top speeds of 300 km h−1 are expected to be operational from Beijing by the year 2020. However, the safety of these routes is affected by the occurrence of land subsidence. This paper focuses on the Beijing–Tianjin Intercity High-Speed Railway (BTR), the first high-speed railway in China, to analyze the operational safety of high-speed railway routes by analyzing both regional land subsidence and local differential subsidence caused by groundwater drawing. The Beijing construction stratum is mainly composed of cohesive soil, and the BTR has a maximum accumulative subsidence of > 800 mm and a maximum subsidence rate of > 80 mm a−1. In this paper, finite-element software ABAQUS is used to analyze groundwater drawdown and land subsidence caused by local water drawing, and its effect on the bearing capacity of railway bridge pile foundations and the orbit concrete supporting course. The analysis provides a technical basis for developing prevention and control engineering measures against land subsidence so as to guarantee the safe operation of these high-speed railway routes.

Capacity constrained accessibility of high-speed rail

This paper proposes an enhanced measure of accessibility that explicitly considers circumstances in which the capacity of the transport infrastructure is limited. Under these circumstances, passengers may suffer longer waiting times, resulting in the delay or cancellation of trips. Without considering capacity constraints, the standard measure overestimates the accessibility contribution of transport infrastructure. We estimate the expected waiting time and the probability of forgoing trips based on the M/GB/1 type of queuing and discrete-event simulation, and formally incorporate the impacts of capacity constraints into a new measure: capacity constrained accessibility (CCA). To illustrate the differences between CCA and standard measures of accessibility, this paper estimates the accessibility change in the Beijing–Tianjin corridor due to the Beijing–Tianjin intercity high-speed railway (BTIHSR). We simulate and compare the CCA and standard measures in five queuing scenarios with varying demand patterns and service headway assumptions. The results show that (1) under low system loads condition, CCA is compatible with and absorbs the standard measure as a special case; (2) when demand increases and approaches capacity, CCA declines significantly; in two quasi-real scenarios, the standard measure overestimates the accessibility improvement by 14–30 % relative to the CCA; and (3) under the scenario with very high demand and an unreliable timetable, the CCA is almost reduced to the pre-BTIHSR level. Because the new CCA measure effectively incorporates the impact of capacity constraints, it is responsive to different arrival rules, service distributions, and system loads, and therefore provides a more realistic representation of accessibility change than the standard measure.