Network Rail has been told to review its assessment procedures for tall walls following an investigation into why a wall collapsed, with 170 tonnes of rubble falling onto a busy line earlier this year.
A section of trackside wall collapsed onto the railway at Liverpool Lime Street station blocking all four lines into the station and damaging overhead wiring equipment at the end of February
An investigation has found that the property adjacent to the cutting had added a soil embankment behind the top of the wall. The increase in ground level subjected the wall to higher loading. Heavy rain could have also contributed to the collapse.
The Rail Accident Investigation Branch (RAIB) found that Network Rail’s examinations had not picked up on the developments and the infringement of its property. It also found Network Rail did not prioritise the risk walls face in terms of the safety consequences of a failure.
The RAIB has now recommended that Network Rail should be aware of walls where a collapse could have a high safety consequence. It also said Network Rail should review its assessment procedures for these walls and how it uses open data to identify changes in land use.
Chief inspector of rail accidents Simon French said the accident could have crushed or derailed a train.
“However, the signs that a dangerous situation was developing had been there for a long time,” he said.
“Network Rail’s examination system did not pick up the significant changes that were taking place behind the wall due to earth moving activities undertaken by the occupier. Similar changes in land use can occur anywhere, especially in areas of urban regeneration. Although I recognise that it can be challenging for the railway industry, it is vital that Network Rail carries out regular and effective checks for activities on its boundaries that may endanger the integrity of its structures. Changes in technology mean that tools, such as aerial surveys, to improve the way in which such information is gathered and analysed, are now readily available.”
Network Rail’s London Northern Western business safety manager Priti Patel said: “Safety is our top priority. The RAIB recommends improvements which we will carefully consider.”