KiwiRail has given details of how much the collapse of state coal mining company Solid Energy has cost it.
Solid Energy went into voluntary administration last year after accumulating unpayable debts of $400 million.
KiwiRail transports the bulk of the company's coal.
KiwiRail chief executive Peter Reidy told Parliament's transport and industrial relations select committee that Solid Energy's failure has hit his company hard.
He said 64 percent of its revenue comes from carrying bulk materials like coal, which has slipped in two years from being a $50 million-a-year business for KiwiRail to a $23m business.
Mr Reidy said many coal wagons were lying empty on unused tracks.