KiwiRail, the state-owned rail and freight operator, said a small fleet of electric trains on New Zealand’s North Island would be phased out over the next two years and replaced with diesel locomotives. The North Island Main Trunk, or NIMT, runs from Auckland to Wellington but is only electrified between Hamilton and Palmerston North with a fleet of 16 almost 30-year old electric trains, Wellington-based KiwiRail said in a statement.