An attempt will be made today to lift the 50-tonne locomotive that fell into Picton Harbour on Wednesday.
File photo. Photo: RNZ / Barry Guy
A remote-controlled shunt locomotive and a wagon with two tank containers sank in the harbour during freight movements at the dock.
KiwiRail chief operating officer Todd Moyle told Morning Report plans were made to minimise impact.
"We had a very successful day yesterday and we last night managed to recover the wagon and the containers.
"So today's the opportunity to recover the locomotive."
He said it would be a difficult feat.
"We have to first thing this morning float it ... about 10 airbags will be required to get that 50-tonne locomotive floating. Then take it around about 15 minutes around the corner to a point that we're able to lift it."
He said there would be two 300-tonne cranes on site.
The weather was good and it would take about two to three hours for the entire operation, he said.
"We've been planning all of these operations around ensuring that we minimise the impact ... we understand acutely the pressure on freight at the moment, and we can't disrupt that while we're doing this operation."
There's been "very limited" discharge from the locomotive into the harbour.
"I think 15 to 20 litres of diesel is about all we've seen, but it's very well contained."
He couldn't say how much this "significant incident" would eventually cost.
"We've been planning all of these operations around ensuring that we minimise the impact" - KiwiRail chief operating officer Todd Moyle