Dynamic heat risk management to reduce the costs of propagating hot weather delays on the railway network.

城市地区不仅有大量的铁路基础设施，而且由于城市热岛效应，气温也会升高。在夏季，这通常意味着城市中的轨道和线旁资产超过关键温度阈值，导致网络局部故障。虽然轨道的其余部分仍然完全可用，但系统的相互依赖性意味着关键节点（即城市地区）的资产故障会在整个铁路网络中传播，导致广泛的延误，乘客不满，以及与原始故障本身不成比例的额外成本。最近的2013年热浪导致伦敦滑铁卢的轨道弯曲和爱丁堡韦弗利的轨道电路故障，这两个影响的例子都得到了明确的强调。为了管理热风险，通常在预定义的温度阈值以上施加毯子速度限制，以确保乘客安全。由于直接故障或更常见的速度限制造成的延误不仅会对乘客造成干扰，而且还会以附表8的形式向使用基础设施的列车运营公司支付巨额费用（即罚款）。本提案探讨了用于热风险管理的现有温度阈值是否合适。特别是，它侧重于确定的可行性，在夏季的过程中增加的动态阈值。这样做的理由是，故障是在炎热时期“收获”的，因此一年中的第一次热浪突出了网络的脆弱性，随后的热浪（除非明显更热）问题较少。这种方法代表了一种激进的创新解决方案，可以减少目前行业中使用的速度限制数量，当气候变化对网络的影响被纳入分析时，其重要性将变得更加明显。

Urban areas contain not only significant concentrations of both railway infrastructure, but also elevated temperatures due to the urban heat island effect. During the summer months, this can often mean that track and lineside assets in cities breach critical temperature thresholds resulting in localised failures on the network. Whilst the rest of the track remains fully serviceable, the interdependent nature of the system means that asset failure at critical nodes (i.e. in urban areas) propagate throughout the rail network causing extensive delays, passenger dissatisfaction, and a disproportionate additional cost than the original fault itself. Examples of such impacts were clearly highlighted during the recent 2013 heatwave which caused the much publicised track-buckle at London Waterloo and track-circuit malfunction at Edinburgh Waverley. In order to manage the heat risk, blanket speed restrictions are often imposed above pre-defined temperature thresholds to ensure passenger safety. The delays caused due to direct failures or, more commonly, speed restrictions are not only disruptive to passengers, but they also cost Network Rail significant money in the form of Schedule 8 payments (i.e. fines) to the train operating companies that use the infrastructure.This proposal explores whether the existing temperature thresholds used for heat risk management are appropriate. In particular, it focuses on determining the feasibility of dynamic thresholds which increment over the course of the summer season. The rationale for this is that failures are 'harvested' during hot spells and hence the first heatwave of the year highlights network vulnerability, with subsequent heatwaves (unless significantly hotter) being less problematic. This approach represent a radical and innovative solution to reduce the number of blanket speed restrictions presently used in the industry, the significance of which will become even more apparent when the consequences of climate change on the network are factored into the analysis.