Communication Based Train Control Research Articles

CBTC 시스템에 대한 시스템 수준의 시험평가 방안 연구

현재 추진되고 있는 무선통신을 기반으로 하는 열차제어시스템 개발 프로젝트에서는 상호운영성 및 상호교환성을 고려하는 하부시스템의 개발을 목표로 하고 있다. 이 프로젝트는 상위 시스템 수준의 설계보다는 주로 하부시스템의 설계에 집중되어 있다. 시스템에 대한 시험평가는 시스템 사양에 대한 만족 여부를 확인하는 것이며, 이에 따라 시스템 수준으로 통합된 시스템 사양서가 필요하다. 본 연구에서는 시스템 사양서가 마련되지 않은 하부시스템의 설계단계에서 최상위 시스템 수준의 시험평가에 대한 방안을 제시하였다.

Radio CBTC for the Las Vegas Monorail

In July 2004, the Las Vegas Monorail entered revenue service with a revolutionary new radio communication-based train control system (CBTC). The radio system is the world’s first application of wireless technology in a revenue-earning urban rail transit system using antennas and over-the-air transmission. The system has performed perfectly and is a testament to the application of sophisticated technology to a challenging environment. The entire data communications system (DCS) serving the CBTC is based on the Ethernet 802.3 open-standard. The radio segment uses the 802.11 extension of this standard to mobile networks. Specifically the 802.11 frequency hopping spread spectrum (FHSS) variant is used because it has the best resistance to interference while providing more than adequate data rates. The entire network was designed and built using commercial off-the-shelf equipment, where the 802.11 standard has been implemented for mobile networks capable of routine hand-overs between access points at up to 100 km/h. The system design, using the standard in the 2.4 GHz ISM band, involved several detailed stages to ensure faultless operation. First the nature of the CBTC data has to be understood and the network has to be designed to accommodate this data. Next the link budgets have to be determined as applied to the unique guideway environment used by the monorail. Signal strength surveys were carried out to determine where to place access points such that there was full and redundant coverage throughout the guideway. Furthermore severe co-user interference (802.11b or WiFi) is present at several locations along the guideway and had to be accommodated. Finally the operating parameters of the radios had to be fully understood to optimize the hand-over process. The complete system was extensively tested and many weeks of data was collected in order to verify that the radio system met the performance requirements.

RESEARCH ON THE SAFETY OF THE COMMUNICATION LINK OF THE RADIO BASED CAB SIGNALING SYSTEM

The Communication Based Train Control (CBTC) system is the development trend of railway signaling. The Chinese railway has made a strategy to develop Chinese Train Control System (CTCS) divided into 5 levels from level 0 to level 4. In level 3 and level 4, CBTC based on GSM-R network will be realized. The Chinese railway is now developing the Radio Based Cab Signaling (RBCS) system as the first attempt on CBTC. Preliminary field tests of the approaching continuous RBCS based in a commercial radio data transceiver have been finished with good results. A long and exhaustive test of GSM-R based RBCS will be carried our on the pilot project of the Qinghai-Tibet railway. Since vital data related to train operation safety is transmitted in the open communication network, it can be easily modified or maliciously attacked and therefore data transmission safety is a vital factor to be considered in GSM-R based RBCS. This paper will focus on data transmission safety in the GSM-R based RBCS, primarily about the cryptographic techniques and key management.

RE-SIGNALLING WITH COMMUNICATIONS-BASED TRAIN CONTROL - NEW YORK CITY TRANSIT'S RECIPE FOR SUCCESS

This paper provides a status report on New York City Transit's (NYCT's) Canarise Line Re-signalling Project scheduled to enter revenue service in 2004. Re-signalling an operating mass transit railway represents many challenges, particularly when introducing new computer-based and communications-based train control technologies. This paper focuses on the project and design management techniques used by NYCT to ensure that the project would be completed on schedule and within budget. The paper will address the techniques used to understand the needs, evaluate the alternatives, develop the implementation strategy, establish the technical requirements, select the preferred system/supplier, promote a partnering philosophy, finalize the system design, and plan the cut-over.

3.6.3 Trade off Between Model Based Systems Engineeing and UML to Develop Communication Based Train Control

AbstractThe purpose of this paper is to evaluate UML for use to model the Communication‐Based Train Control (CBTC) system for an Automated Guided Transit (AGT). In the previous study, a computer‐aided systems engineering tool, CORE from Vitech Corp., was used for the same purpose. The study demonstrates UML diagrams illustrating the system view obtained at each development life cycle such as operation concept construction, requirement analysis, functional analysis, and synthesis phase. This research attempts to establish not only a smooth interface with software engineering, but also various system views unavailable from the traditional systems engineering tools. As a result, there are more abundant system representions that facilitate the system design process.

Developing Standards For New Technology SignalSystems For Rail Transit Applications

Radio communications-based train control (CBTC) systems, also referred to as transmission-based signalling (TBS) systems, permit more effective utilization of rail transit infrastructure by allowing trains to operate safety at much closer headways, by permitting greater flexibility and greater precision in train control, and by providing continuous safe train separation assurance and overspeed protection. One of the challenges facing transit agencies who are considering the

AT ACS: First Phase Control System And ItsExperimental Test Results

The test run of AT ACS (Advanced Train Administration And Communications System)** which is managed by East Japan Railway Company was carried out. AT ACS is a radio communication-based train control system. Hitachi, Ltd. developed three field controller sets (a set constructed form a main controller and a sub-controller), two management servers and two sets of a on-board controller for two test trains. Outputs from main and sub-field controllers are mixed and transmitted to vehicles, and these data are verified by the on-board controller. Virtual trains generated in field controllers were also used in field test runs. Open & close control and handover control of communication channels were performed in the field controllers. A hazard state never happened in these test runs. Transactions on the Built Environment vol 34, © 1998 WIT Press, www.witpress.com, ISSN 1743-3509

Train Dispatching Effectiveness with Respect to Communications-Based Train Control: Quantification of the Relationship

This analysis presents a methodology for measuring the efficiency of train dispatching as a product of three variables: (a) the type of train control system (measured by latency, defined here as the interval between occurrence of a schedule deviation and initiation of corrective action); (b) the physical capacity of the route (track kilometers per route kilometers); and (c) train minutes per route kilometer (a measure of both capacity and dispatcher competence). A mathematical relationship among these three variables is postulated, and a log-log regression analysis is used to develop coefficients that relate each of the three independent variables to dispatching efficiency. To do this, actual train-movement data and minimum train running times for 28 U.S. Class I railroad line segments are used. Results of the regression analysis indicate a statistically valid relationship among latency, track capacity, traffic volume, and dispatching effectiveness. Dispatching effectiveness, calculated by placing track kilometers per route kilometer, train minutes per route kilometer, and latency at their mean values, was 71.3 percent (the mean latency was about 17 min). At a latency of 3.5 min, average effectiveness is 81.3 percent. Examples of the trade-off between latency and effectiveness and between track capacity and effectiveness also can be calculated. For the average line, when latency is progressively reduced from the current value of 15 min to 3.5 min, dispatching effectiveness increases from 71.3 to 81.3 percent. When track kilometers per route kilometer are increased from the average value of 1.3 to 2.0 (double-tracking the entire railroad, holding all other values constant) dispatching effectiveness can be increased from 71.3 to 89.5 percent—a larger increase than that realized from a reduction in latency, but at much higher cost. To quantify the dollar benefits of such an increase in dispatching effectiveness for U.S. railroads, further analyses were carried out. Based on a previous study of Burlington Northern operations, train delay costs ranged from $163/hr to $266/hr. To simplify calculations, a value of $200/hr is used. According to U.S. railroad statistics, there are about 21 million train hours of traffic each year. Benefits available from installing communications-based train control are calculated in terms of additional train minutes per route kilometer available with an increase in dispatching effectiveness based on this analysis. Based on this analysis, it should be possible to save (1 − 0.713/0.813) or 12.3 percent of total train hours. The benefit of this would be $200 × 0.123 × 21 × 10 or $520 million annually. The Association of American Railroads has estimated the cost of positive train control for the entire U.S. railway network to be between $843 million and $1.1 billion.