What the risk is and who it affects

Civil Engineering Assets include structures, earthworks, operational property and drainage systems. Their integrity is fundamental to safe railway operation. Failure of these assets can lead to derailment, potentially resulting in multiple fatalities, or can cause injury to staff, passengers and the public through falling parts, structural collapse or track obstruction.

Failures may occur suddenly, particularly during extreme or localised weather, and can arise from earthwork movement, drainage failure, scour, masonry collapse or impacts from ancillary structures. Such failures can obstruct the line or distort the track, creating risk to train operations.

Risks affect:

• Passengers and public (structural collapse, falling debris, station asset failure)
• Train operations (derailments, collisions following track obstruction)
• Staff and maintainers (defects in inaccessible or hidden locations)
• Dutyholders (managing degraded, ageing or poorly understood assets)

Fundamental risks

Significant factors influencing civils assets risk

Long-term exposures and system-level risk

Civils assets form part of a wider infrastructure system. Culverts, drainage, earthworks and track are interdependent; poor performance of one can generate defects in another. Neglect of drainage assets has also historically contributed to instability and defects. An infrastructure system risk management approach is required.

Civils assets are also vulnerable to actions by outside parties such as diverted drainage, water mains leakage, or changes in land use. Incidents at Corby and Barrow-upon-Soar show how third-party actions can rapidly create hazards without warning.

Ancillary structures, numbering in the hundreds of thousands, also present risk when examinations do not identify deterioration (e.g. Newbury signal post collapse). These assets include signal structures, OLE and telecoms masts, walkways, lighting columns and hoardings, and have been associated with an increasing number of incidents.

There are 17 major and 2,500 other stations and 8,200 commercial properties on the national network, with a further 270 stations on LUL and others on the light rail and heritage networks. These all require routine inspection, examination and assessment to ensure continued safe operation.

Emerging trends and weather-driven risk

Extreme weather events (heavy rainfall, convective storms, ground saturation, high winds) significantly increase the likelihood of Civils assets failures. Earthworks are particularly susceptible to rainfall-driven failures, and structures are at risk from scour.

Climate change has already resulted in more frequent and severe events. ORR’s risk profile shows that weather-related precursors are a major driver of Civils assets failure risk and will remain so for future decades.

ORR’s enforcement experience shows that even well managed and maintained infrastructure can fail under extreme conditions. Therefore, consequence management must be strengthened, as elimination of risk through renewal alone is sometimes not reasonably practicable for ageing infrastructure.

Sector differences (who is affected?)