KiwiRail chief executive Peter Reidy has written a personal opinion piece to explain the national rail operator’s decision to purchase diesel locomotives to replace ageing electric locomotives for a section of the North Island Main Trunk (NIMT) Line.

In the piece, Mr Reidy acknowledged the decision was “never going to be easy”, but was taken after careful consideration of all options in a 24-month period of consultation with affected stakeholders.

“Our strategy of simplify, standardise and invest has been hindered by effectively operating a railway within a railway — diesel trains to Hamilton, then electric, then back to diesel again,” he stated.

“The complexity of the electric/diesel mix also meant having to employ drivers and mechanics with specific electric fleet knowledge or engineering skills. It meant more complicated train plans and load schedules.

“Some will ask why KiwiRail couldn’t just make the whole NIMT electric? That would cost $1 billion or more and would also require the networks feeding into the NIMT to be electrified as well, something estimated to cost $2.5 million per kilometre of single track. One day that might make sense but there are challenges such as the Wellington area’s electric network running on a different power system to Auckland’s.”

Addressing criticism about the environmental ramifications of the decision, Mr Reidy noted that even using diesel locomotives was better for than environment contrasted to those cargoes otherwise being moved via road.

Furthermore, Mr Reidy emphasised this was “not a forever decision”.

“Even though diesel trains are the best option for KiwiRail right now, the electric infrastructure will continue to be maintained on the line, leaving that as an option should it be required in the future.”