折返站是限制轨道交通线路运营能力的关键点，因此折返站的设置在地铁设计过程中至关重要。鉴于目前建设过程中车站尾部常常受到建设规模的制约，从信号系统设计的角度就站前折返安全距离长度对站前折返能力的影响进行分析。首先根据IEEE制定的CBTC系统安全制动模型，推导安全距离计算模型，根据计算模型得出安全距离缩短后对信号系统ATO控制列车运行的影响。其次，通过仿真模拟列车站前折返全过程，绘制折返时间图解，研究站前折返能力的受制因素，分析列车安全距离缩短后对折返时间间隔的影响。最后，从信号系统设计的角度提出在安全距离受限的情况下有效、合理的解决方案。

The turn-back station is a key node in rail transport capacity. Therefore, the turn-back station design plays a vital role in a subway system. In the process of modern construction planning, we are confronted with problems where the end of the station is dictated by the scale of the construction. On the basis of such a constraint, this paper analyzes the effect of the safe distance on the headway for turn-back capacity from the signal system perspective. First, based on the communi-cations-based train control (CBTC) system safety braking model, a safety distance calculation is deduced. According to the calculation model, the effects of shortening the safe distance on automatic train operations are studied. Second, by computer simulation of the process of a train turn-back, a turn-back time diagram is plotted to study the factors influencing turn-back capacity when the safe distance of the headway for a turn-back station is shortened. Effective solutions to improve station turn-back capacity under the safe distance constraint from the perspective of the signal system are then proposed.

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