Three people have died after a passenger train derailed on Wednesday, following a night of heavy rains. Six other people were taken to the hospital for treatment.
"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," Haynes said, as quoited in a public statement.
Earlier in the day, Scotland's First Minister Nicola Sturgeon said that authorities had launched a probe into the accident and vowed to make sure that "any necessary lesson are learned."
A landslide is believed to have played a role in the incident, which saw the train leave the line before bursting into flames, according to domestic media reports.
Some regions of eastern Scotland were hit with torrential rain overnight that led to flash flooding and landslides. According to the Met Office, more than three inches of rain fell in a matter of hours, as severe thunderstorms brought heavy downpours.