How does weather affect our assets?
Weather is what can be observed over a short period of time, such as intense or prolonged rainfall, heatwaves, cold snaps, hurricanes and snow. For example, excessive rainfall can flood our infrastructure or destabilise the lineside, making the earthworks susceptible to landslips.
The images below show how weather can affect our assets, damage our infrastructure, and cause delays. An explanation of these delays is explained on the Network Rail website.
How does weather impact the railway?
The main impacts of weather on the railway are: costs, poor performance (measured by Public Performance Measure (PPM), and safety risks.
Over the past 12 years adverse weather conditions resulted in an average 2-3% reduction in PPM achievement across the railway network. The impacts of extreme weather can be more significant, with large variations from year to year.
Weather impacts cost us £50-£100m per year due to delays and cancellations. If the wider costs to the railway and the economy are included (for example missed targets, repairs and socio-economic impacts) this rises to £200–£300m a year.
From a safety perspective, fortunately, we have not had any serious accidents caused by the impacts of weather events in recent years. However, the landslip at Watford in September 2016 and bridge scour at Lamington in December 2015 are reminders of the potential for serious consequences.
The figure below shows the delays associated with weather-related incidents across the network for the past decade. Further detail on delays can be found on the National periodic reports page and by Route, in the form of periodic reports using the links in the side-bar.
From 2012 through to 2017 frequent and severe flooding was the main weather factor affecting train delays, however, in more recent years the pattern has changed. The year 2017-2018 saw a particularly large number of delay minutes from snow, a stark contrast from 2018-2019 which saw many delay minutes from heat. The increasing number of S8 delay minutes has focussed attention on the need for key infrastructure to be resilient to current and future weather extremes.
In response, the government and our regulators are seeking assurance that we understand the risks of our changing climate and are acting to enhance resilience and adapt to the impacts, both now and in the future. In 2015 we produced an overarching Climate Change Adaptation Report (available in the side-bar) for Defra which summarised our progress towards understanding the potential impacts of climate change on the performance and safety of the rail network, and actions taken to increase resilience. We will be producing our third Adaptation Report for Defra in 2021.
Climate change will cause existing weather patterns to shift, changing the severity, frequency and impact of events. Maintaining, and improving, our resilience will become increasingly challenging as these changes amplify the risk and impact of asset failures to unacceptable levels. Such shifts will mean that our historic records of likelihood, severity and impact cannot be relied upon to inform our future operational and investment decisions. We are working to increase our understanding of the changes on risk so that we can plan when, and how, we will need to adjust our responses to cope with the new normal.
What are we doing to manage the risk?
In 2017 we produced a Weather Resilience and Climate Change Adaptation (WRCCA) Strategy which aims to deliver a railway that is safe and resilient to the effects of weather, now and in the future. It lays out the key principles and actions necessary to get to the position where weather and climate risk management is embedded in decision making processes across the business.
By embedding future weather consideration into business planning and asset management processes we will increase the resilience of the railway; reducing weather-event related safety, performance and cost impacts.
The delivery of WRCCA actions in the Routes is through individual Route WRCCA plans the current plans can be accessed on Route-specific pages in the side-bar. These were first published in 2014 and updated versions will be published in 2019 to reflect new analysis, control period investment plans and updates to the UK Climate Change Projections.
Underpinning all our work is analysis of operational weather impact data to improve our understanding of our current and future risks to inform our resilience planning and responses. For further information follow the Route links in the sidebar.