Kiwirail is planning to undertake maintenance along the rail line between Milburn and Milton, picking up, cleaning and re-depositing ballast (rail formation material) in the next few weeks.
About 5000 sleepers would also be used for routine "resleepering" between Sawyers Bay and Waitati, a KiwiRail spokeswoman said.
A large EM80 ballast cleaner would move along the track between Milburn and Milton, she said.
Overall, the equipment occupied about about 348m of track when in operation.