Network Rail engineers are now relaying over 500 metres of track following the recent completion of work to repair the bridge and embankment damaged in the accident.
Work will continue into November as engineers remove and replace the damaged track and relay 400 metres of telecoms cables.
Teams have worked round the clock over the past few weeks to complete repairs to 70 metres of bridge parapets and remove the crane pad built over the Carron Water for the recovery of the carriages in September.
Network Rail also says that a considerable amount of engineering work is also being carried out to repair and extend drainage systems on the railway track and lineside embankments at the site.
The 06:38 ScotRail Aberdeen to Glasgow Queen Street service derailed on August 12 after striking a landslip with the devastating loss of three lives - driver Brett McCullough, conductor Donald Dinnie, and passenger Christopher Stuchbury.
Alex Hynes, managing director of Scotland’s Railway, said: “This is a very complex and challenging recovery and repair operation and it will take time for our engineers to fully restore the track and other infrastructure.
“While we will reopen the line for customers as soon as possible, our focus throughout the recovery process has been on making sure we do all we can to learn from this terrible accident and try to prevent similar incidents happening in the future.”
ScotRail is operating a shuttle service between Aberdeen and Stonehaven and between Dundee and Montrose to keep customers in the north east moving. A replacement bus service also remains in place between Dundee and Stonehaven, and between Dundee and Aberdeen.
Cross-border operators are also running replacement buses between Aberdeen and Edinburgh.
A report on the rail network’s resilience to extreme weather following the Stonehaven derailment was submitted to UK Transport Secretary Grant Shapps last month.
Investigators found that in the four hours before the crash, 75 per cent of Aberdeenshire’s total average August rainfall had fallen in the area.
Their report said a drain carrying water from land above the line washed rocks and gravel onto the tracks.
Network Rail has since introduced a range of additional safety measures which followed the crash
Hundreds of sites nationwide with higher-risk trackside slopes, similar to Stonehaven, were inspected.
These inspections were carried out by both in-house engineers and specialist contractors, supplemented by helicopter surveys.
Network Rail has also launched two taskforces, led by independent experts, to meet the challenge of maintaining its massive portfolio of earthworks – embankments and cuttings – many of which date from the Victorian era.
Dame Julia Slingo FRS, former chief scientist at the Met Office and a world-renowned expert in climatology, is leading a weather action taskforce with the objective of better equipping Network Rail to understand the risk of rainfall to its infrastructure.
Lord Robert Mair CBE FREng FRS is spearheading an earthworks management taskforce to see how Network Rail can improve the management of its earthworks portfolio, looking at past incidents, latest technologies and innovations and best practice from across the globe.