The Development of the Operational Risk Analysis System for Taiwan Railways Administration

台鐵為國內主要的軌道運輸系統之一，面對其他運輸系統的競爭，應積極提升台鐵行車系統的營運績效；然過去國內軌道系統風險評估與管理之相關研究多著重於行車事故對於系統安全之影響，較少探討事故對於營運風險的影響，故本研究提出一個行車營運風險分析系統，從行車營運的觀點進行軌道風險評估，並以台鐵行車事故資料進行案例分析。 本研究所提出之分析系統主要包括六個模組，首先，以「行車事故基本資料模組」進行事故記錄的分類建檔與敘述性統計分析，並同時利用「路線使用量轉換模組」將時刻表轉換為各時段路段下的「路線使用量」，以供後續發生機率曝光量之計算；接著透過「事故發生機率分配詴合模組」分析之驗證結果，顯示各類事故的「發生間隔」皆服從指數分配，因此，根據指數分配的無記憶性，可知無論前一時段路段營運之列車小時多寡，事故發生機率僅與該時段路段下的營運列車小時數有關；延續上述結果，以「行車營運風險模組」分別估算於同一時刻表下各路段時段的期望延誤時分，並於加總後輸出目前台鐵之行車營運風險值。而「維護度分析模組」則是輸出各類行車事故的維護度函數，藉以評估行車系統於各類事故發生後的修復能力。最後，在總風險必頇低於可接受風險的前提下，本研究之「風險對策選擇模組」可考量各項風險對策的改善成效，以最小化總改善成本為目標，輸出建議之風險對策，以供台鐵參考。 利用本風險分析系統，可從行車營運的角度，考量時刻表對事故發生機率的影響，估算行車系統營運一日的期望延誤時分，並透過各類事故的維護度函數，估計在給定時間內事故修復的機率，做為風險對策研擬之參考，進而促進行車營運績效的提升。Taiwan Railways Administration (TRA) is one of the most important railway systems in Taiwan. In order to face the competition come from other transportation system, TRA should actively improve the operational performance of train system. The risk assessment and management of a railway system were mostly focused on the safety issue in past researches. Thus, this study provides a framework of the railway operational risk analysis system in aspect of train operation, and the framework illustrated within the case study of TRA with an accident history data. The risk analysis system includes six modules. Firstly, train accident data module classifies and compiles the train accident historical data, and a usage of route module is used to transform the route usage under specific period of the timetable for the computation of probability of accidents. Then, the probability density functions of train accident module assume the time intervals of train accidents are valid for the exponential distribution in the aspect of reliability. According to the memoryless of exponential distribution, probability of accident is only related to the operational train-hours in a section. Next, an operational risk analysis module is utilized to calculate the expected delay of each section under a timetable, and summation of expected delay of each section is considered as the operational risk. Through the maintainability analysis module can assess the repair ability of a train system. Finally, the risk treatment selection module is introduced for the purpose of reducing the system total cost and risk. Under the premise of minimizing the system total cost, the strategy of each subsystems in defined by this study. This analysis system can evaluate the operational risk and promote the operational performance