COLLEAGUES “thought the world” of the train driver killed on Wednesday in the Stonehaven derailment, a union official said today.

Brett McCullough, 45, was a former gas engineer who decided to switch careers after servicing the boiler of a railway worker.

He leaves behind behind wife Stephanie and three children — two girls and a boy.

Train drivers’ union Aslef Scotland organiser Kevin Lindsay said: “The tragic accident at Stonehaven has affected everyone in the railway family. 

“Brett thought the world of his family, and his colleagues thought the world of him.

“There will be an investigation into the causes of the crash, and we will learn those lessons, as we have in the past, because the railway is one of the safest modes of transport.”

The 6.38am Aberdeen to Glasgow Queen Street service derailed near Stonehaven on Wednesday morning amid heavy rain and flooding. Three people were killed and six injured.

The train’s conductor Donald Dinnie and a passenger also died in the crash.

Network Rail is to inspect high-risk trackside slopes across Britain following the Aberdeenshire crash.

Network Rail boss Andrew Haines, who arrived at the scene today, said: “Questions are inevitably being asked as to how this could happen and I am determined that we understand the circumstances that led to this devastating event.

“It’s too early to draw conclusions but it is critical that we investigate thoroughly and with care, and work closely with rail safety authorities to make sure this can’t happen again.”

A landslip amid heavy rain and flooding is suspected to have played a part in the accident.

An inquiry has been launched by the Rail Accident Investigation Branch.