The cutting at Barnehurst, on the Bexleyheath line between Lewisham and Dartford, Kent, reopened on Monday 18 February after being closed for a week.
When the cutting face slipped at around 03:30 on the morning of Monday 11 February, it was the fourth time it had done so since 2010.
Opened in 1895, the cutting faces are steep, which lays them open to problems with slips. As Derek Butcher, Network Rail’s route asset manager for geotechnical engineering, explained, the cutting was already monitored using both CCTV and remote condition monitoring.
So when the cutting face slipped without warning, the monitoring alarms allowed the railway to be closed with no risk to passengers.
After examination by engineers, the decision was taken to clear the site and then to make the cutting safe by using H piling – H-shaped steel beams driven into the ground with concrete panels between them to build a wall that will prevent slippage in the future.
300 tonnes of earth and trees were removed and then work could start on the 30 metres of wall.
Piling was finished by Friday 15 February and the wall infill panels completed over the weekend.
Work was also undertaken to ensure the track was safe, replacing and replenishing contaminated ballast, and after test trains ran through on Sunday evening to check the repairs and test the signalling, the railway was ready to open on Monday.