The train derailment that killed three people last week occurred after almost three-quarters of Aberdeenshire’s monthly rain fell in just four hours, investigators have revealed.
New details have emerged about the circumstances of the tragedy, which happened at Carmont, near Stonehaven.
Conductor Donald Dinnie, train driver Brett McCullough and passenger Christopher Stuchbury died, and six others were injured, when the 6.38am ScotRail service from Aberdeen to Glasgow Queen Street derailed.
Now, the Rail Accident Investigation Bureau (RAIB) has published additional findings about what happened in the moments leading up to the accident.
The train had departed on time from Aberdeen and then Stonehaven, but was stopped by a signaller at Carmont at 6.59am because a landslip was obstructing the line between Laurencekirk and Carmont.
It was stopped there for more than two hours before being given permission to return north to Stonehaven at 9.25am.
The report said the train reached speeds of 72.8mph when it struck a landslip covering the line at about 9.38am and derailed.
The RAIB said this was “within the maximum permitted of 75 mph (120 km/h) on this stretch of line”.
According to weather records, between 5am and 9am around 52mm of rain fell in the Carmont area. This is almost 75% of the total monthly rainfall (70mm) for Aberdeenshire in an average August.
New pictures from the scene show investigators still working to establish further details about the crash – why it occurred, and how something similar can be prevented from happening again.
Ali Chegini, director of system safety and health at the Rail Safety and Standards Board, said: “As far as RAIB are concerned, they really are at the forefront of doing this kind of thing anywhere in the world.
“The first thing they do is develop a strategy for how they will conduct that particular investigation.
“The key thing is to ensure that perishable evidence – evidence that establishes things such as temperature and pressure, things that deplete with time – is gathered very quickly.
“Sometimes the industry gets a little bit frustrated, because they really do go to the nth degree, not only to establish facts but also to rule out other things.
“They come at information from several angles – the train will have an on-train recorder which will tell you exactly what happened in the lead-up to the tragedy, but they will also look at it from a physical evidence perspective, by taking distances and measurements.
“It really is meticulous, in that there is nothing left to guesswork.”
He added: “The challenges they do face include the topography and terrain, just access to that site to be able to get the power and electricity for lighting.
“RAIB take a lot of photographic evidence, and for that they need good lighting.
“It is a difficult site to ensure you’ve got your own safety, and in the time of Covid you have all the issues around infection and making sure people are safe while working in close proximity to each other.”
Following the release of the investigation update, train driver Brett McCullough’s wife Stephanie posted a tribute to her “kind, gentle” husband on social media.
And she stressed that her husband had followed the instructions of his employers on the day of the accident.
She said: “Brett did what he was told. We know this because the “black box” recorded Brett’s speed that was under the speed limit and the communications between Scotrail and Brett record everything!
“We also know Brett saw the landslide because the emergency breaks were applied. I can’t stand people implying that my beautiful kind husband was to blame.
“He did everything he was told to do. Nobody should go to work and not come home. I have three heartbroken children here who Brett adored. His family was his world and he cared so much about people.
“Nobody can say a bad word about my kind gentle husband.”