Properties of train traffic flow in a moving block system

The development direction of railways is toward the improvement of capacity and service quality, where the service quality includes safety, schedule, high speed, and comfort. In light of the existing cellular automaton models, in this paper, we develop a model to analyze the mixed running processes of trains with maximal speeds of 500 km/h and 350 km/h respectively in the moving block system. In the proposed model, we establish some sound rules to control the running processes of a train, where the rules include the departure rules in the intermediate stations, the overtaking rules, and the conditions of speed limitation for a train stopping at a station or passing through a station. With the consideration of the mixed ratio and the distance between two adjacent stations, the properties of the train traffic flow （including capacity and average speed） are simulated. The numerical results show that the interactions among different trains will affect the capacity, and a proper increase of the spatial distance between two adjacent stations can enhance the capacity and the average speed under the moving block.

Energy Saving for Automatic Train Control in Moving Block Signaling System

With rapid development of the railway traffic, the moving block signaling system （MBS） method has become more and more important for increasing the track capacity by allowing trains to run in a shorter time-headway while maintaining the required safety margins. In this framework, the tracking target point of the following train is moving forward with its leading train. This paper focuses on the energy saving tracking control of two successive trains in MBS. Nonlinear programming method is used to optimize the energy-saving speed trajectory of the following train. The real-time location of the leading train could be integrated into the optimization process. Due to simplicity, it can be used for online implementation. The feasibility and effectiveness are verified through simulation. The results show that the new method is efficient on energy saving even when disturbances present.

Application of Permutation to Moving Block Bootstrap

The method of permutation is introduced for the block re, sampling of moving block bootstrap, and is compard with the fixed block bootstrap and stationary bootstrap. Simulations are proformed, which verify that the block resampling of moving block bootstrap with permutation can effectively eliminete the number of abnormal data in the resampled data set and reduce the resampling errors of estimation.

Station Model for Rail Transit System Using Cellular Automata

In this paper, we propose a new cellular automata model to simulate the railway traffic at station. Based on NaSch model, the proposed station model is composed of the main track and the siding track. Two different schemes for trains passing through station are considered. One is the scheme of ＂pass by the main track, start and stop by the siding track＂. The other is the scheme of ＂two tracks play the same role＂. We simulate the train movement using the proposed model and analyze the traffic flow at station. The simulation results demonstrate that the proposed cellular automata model can be successfully used for the simulations of railway traffic. Some characteristic behaviors of railway traffic flow can be reproduced. Moreover, the simulation values of the minimum headway are close to the theoretical values. This result demonstrates the dependability and availability of the proposed model.

Experimental Field Study of Movement Charateristics of Rock Blocks Falling down a Slope

The downslope movement of detached rock blocks along steep slopes is an important process endangering the safety of infrastructure along the foot of a slope and on the valley bottom,but only limited knowledge is available on the influence of various factors on the velocity and distance of movement of such blocks.We discuss the influence of the mass and shape of the rock blocks,the steepness of the slope,and the thickness of the overburden on the slope,on the distance of movement of rock blocks which was observed in 256 field experiments with differently shaped blocks from 3 different positions on the slope with a height of 176 m.The statistical evaluation of the results of the field tests shows that the slope condition of gradient and overburden is the main factor,the form of rock masses is the second factor,and the mass is the third of the influencing factors.It is the maximum average acceleration for movement of rock masses when the mass of rock masses is 15≤m27 kg,the form of rock masses is flake,the condition of gradient is on average 59.6° and the overburden is basic exposed bedrock and a small quantity of gravel-soil in the experiment condition.It is the minimum average acceleration for movement of rock masses when the mass of rock masses is 9.5≤m15 kg,the form of rock masses is rectangular,the condition of gradient is on average 39° and the overburden is gravel-soil and cinder.Then,the foundation for impact energy is provided and the new feasible methods to prevent potential unstable rock masses are put forward.

ERTMS/ETCS Level 3:Development,assumptions,and what it means for the future

The purpose of this paper is to categorize the research on Level 3 and Hybrid Level 3;map how the research focus on ERTMS Level 3 has developed over time;summarize key assumptions in research on Level 3 and Hybrid Level 3.This study uses a scoping review approach.This review method provides a comprehensive overview of the literature in a selected field.The literature searches in this study were primarily conducted in Scopus and Web of Science and were complemented with a follow-up search in Google Scholar.The topics are divided into two thematic areas:Effects on the Railway System and Technical Requirements.The thematic area Technical Requirements is further divided into the following subcategories:train,trackside,and communication.The effects on the railway system are measured using performance indicators:capacity,stability/robustness,and safety.ERTMS Level 3 has developed from a pure Level 3 to Hybrid Level 3.Hybrid Level 3 represents a pragmatic solution,but it may emerge as a threat to the long-term objective of the Level 3 moving block.Studies of Level 3 are based on a moving block solution,while studies of Hybrid Level 3 are mainly based on virtual sub-sections.Both Level 3 and Hybrid Level 3 studies tend to make assumptions that risk missing wider aspects of the railway system.There is also a need to correctly represent different ERTMS Level 3 configurations to ensure expected capacity gains.For a better understanding of the development and future path of ERTMS Level 3,it is interesting to study the following aspects:the historical development of ERTMS Level 3 research,the assumptions made about ERTMS Level 3,and the conditions and restrictions under which ERTMS Level 3 will be implemented.Assumptions and simplifications are necessary for modeling work,but there is also a need to highlight underlying assumptions in analyses of different ERTMS Level 3 configurations.

Modeling and Simulation for Urban Rail Traffic Problem Based on Cellular Automata

Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.