The train had to be pulled out of the tunnel and backed up towards Inangahua.
When the Greymouth Star observed the slip clearance on Sunday, material was clearly dribbling down into the Buller River with the aid of mechanical diggers.
West Coast Regional Council acting consents and compliance manager Rachel Clark said the council was in close contact with KiwiRail around the clearance work.
"They are able to undertake the works as emergency works."
Last week, Westland Mineral Sands managing director Ray Mudgway referred to the vulnerability of the Buller Gorge railway, and the need for a coastal shipping option to provide more resilience.
The massive slip, blocking the rail route out of the Stockton coal mine, was likely to go on for more than two months, he said.
