Jim Bolger is to be replaced as chairperson of the board of state-owned KiwiRail at the end of June.
Mr Bolger, a former prime minister of New Zealand, has headed KiwiRail's board of directors since it was established in 2008.
His replacement will be Wellington company director John Spencer, who will step aside from his role as deputy chair of Solid Energy since 2006.
Mr Spencer, who led the merger of Asure and AgriQuality in 2007, will take over as chairperson in July.
State Owned Enterprises Minister Simon Power thanked Mr Bolger for his service, saying he has been a strong leader for KiwiRail.
Mr Power says he is confident Mr Spencer will successfully guide KiwiRail through the challenges ahead.