Rail accident 

Impact 5
upper risk error bar
upper likelihood error bar
risk indicator
lower likelihood error bar
lower impact error bar
Impact & Likelihood
Impact key
5 Catastrophic
4 Significant
3 Moderate
2 Limited
1 Minor
Likelihood key
5 >25%
4 5-25%
3 1-5%
2 0.2-1%
1 <0.2%


Although UK railways are among the safest in Europe, there is still a risk that a rail accident could occur. Trains operate at high speeds and constitute a significant mass, meaning that any accident has the potential for significant consequences. A recent example of a rail incident is the 2021 Salisbury rail crash, which resulted in the derailment of 2 trains and 14 injured. A robust safety framework, with an active safety regulator and independent accident investigation body, is underpinned by a legislative framework with a clear allocation of responsibilities
and duties to all bodies operating on, or around the railway.


The reasonable worst-case scenario is based on a serious rail accident that causes multiple casualties or fatalities, or significant environmental or economic damage. There would be damage to property and infrastructure within the affected area, and potential evacuation of those affected. There may also be environmental damage or contamination. Impacts on the railway network would be widespread, with lines being temporarily closed for weeks due to the damage to the infrastructure. This would impact passenger journeys by causing delays, reduce accessibility to specific regions and affect supply chains.


A variety of circumstantial factors may contribute to the risk and impact of an accident. These include weather, human factors, time of day, speed, geography, number of passengers, contents being transported and interaction with infrastructure.

Response capability requirements

A quick coordinated response between operators, Network Rail, the Office of Rail and Road, the Rail Accident Investigation Branch, local authorities and emergency services (including police and fire and rescue services) would be required to mitigate the impacts of a rail accident and reduce potential for subsequent harm. The industry has experience of managing rail accidents and has procedures and processes in place on how to effectively respond. Where dangerous materials are involved, emergency procedures would need to be rapidly implemented working with the relevant authorities.


Some derailments can put a line out of commission for several weeks (or up to one month or more if very severe) due to damage to infrastructure and recovery. Lines are also usually closed temporarily while authorities assess the damage and begin investigations (investigations are not always carried out, but are determined on the basis of harm/economic damage and whether new information or lessons can be learnt). The amount of time this takes will depend on the location of the site, weather, degree of damage or the complexity of factors locally. After testing, the line can be returned to service. Where an accident is caused by asset failure (for example tunnel or bridge collapse) return of service could be several months or years.