A report into the derailment of a passenger train which led to disruption for commuters has come up with a series of recommendations for Network Rail.
The Rail Accident Investigation Branch (RAIB) report focused on a derailment which happened as the three-coach train approached Waverley station, Edinburgh, on July 27 last year.
The train, which had no passengers on board, was travelling from Cowdenbeath, Fife, to the capital when it came off the tracks in the Princes Street Gardens area just before 6pm. Neither the driver nor conductor were injured in the incident, which happened at a slow speed and left the train upright.
The derailment caused damage to points and the track, as well as part of the train and signalling cables.
The RAIB report found attempts were made to repair a section of the track days before the incident, although it was "worn beyond repair". A subsequent inspection of the section after the repairs were carried out did not find it to be unsafe, the report found.
The 60-page report by investigators concluded that the first wheel to derail had not been correctly steered by the "moveable switch rail" onto the correct route. Instead, it climbed over the rail, pulling other wheels off the track. The report also found that on July 24 and 25, a section of track had been repaired.
It stated: "Three days prior to the accident the left-hand switch rail had been identified as having the potential to cause derailment. Although it was worn beyond repair by grinding in accordance with the company standard, a grinding repair was attempted. The subsequent inspection process did not find the switch to be unsafe and it remained in service.
"The required prior scoping of the repair, which might have identified the unsuitability of the switch rail for repair by grinding, was not carried out. The local practice of maintaining points to safety limits and the lack of guidance on when a switch rail is unrepairable by grinding were underlying factors in this accident."
The RAIB issued five recommendations to Network Rail around its work and repair procedures. Among them was a suggestion that Network Rail needs to "review and address the recurrence of factors in this accident which were previously identified by the RAIB in investigations of similar derailment".
Network Rail said it made changes to ways of working after the accident. A spokesman said: "Safety is our number one priority and we will review the RAIB report closely. We have already made changes in how we manage the maintenance of points and reviewed staff training as a result of this incident."