His latest position involved driving passenger trains from Wellington to Waikanae, Johnsonville, Upper Hutt and Melling. The determination stated he was also a tutor driver with KiwiRail, helping to train other drivers.
Following the collision, at a meeting between KiwiRail and Mr Thorne's lawyer, he admitted to smoking a cannabis cigarette 11 days before the incident, the determination stated.
He said he was not a regular smoker, but had done so because he was upset following a falling out with a family member.
He went on to say he did not think he had been impaired at work when he returned the following Monday, and he had carried out his train driving duties with no issues for the week until the collision.
The authority's determination stated Mr Thorne was aware of the company's "zero tolerance" drugs and alcohol policy and he acknowledged that he had made a mistake in smoking cannabis.
However, he said he believed he was not impaired by the drug, which was why he showed up for work the following week.
He also said he believed KiwiRail had not considered any alternatives to dismissal -- citing examples where other employees had tested positive for drugs, as he did, but were not dismissed and were instead instructed to undertake rehabilitation and remained working for the company.
Mr Thorne's lawyer also said KiwiRail failed to take his length of service into account.
However, KiwiRail's HR manager Victoria Clark said the public had to have confidence in the service which provided rail transport for thousands of passengers on a daily basis.
She also used Pike River as an example of the greater responsibility being put on employers.
Authority member Trish MacKinnon said that while dismissal was not the only option available to KiwiRail, "it was an action that a fair and reasonable employer could take" and subsequently dismissed Mr Thorne's appeal.
KiwiRail declined to comment. Mr Thorne could not be reached.
