KiwiRail has revealed it lost $12 million in revenue and costs in the six weeks following the Kaikōura earthquake.
The state-owned rail company has released its half-year results to 31 December last year, showing it returned a surplus of $11m.
Chief executive Peter Reidy said it lost $9m in revenue between 14 November, when the quake hit, and the end of the year.
It took a further $3m hit in costs.
The biggest impact was on domestic freight because of the closure of the Main North Line but the scenic Trans Alpine and Coastal Pacific services were also affected by line closures, he said.
The fall-out from the earthquake would continue to eat into operating surpluses for this half, he said.
However, Mr Reidy said he was pleased the company was still able to deliver a surplus in spite of the earthquake.
The company was on track to make productivity savings of $18m by the end of July.