KiwiRail engineers have identified the fault that forced the interisland ferry Arahura to drop anchor when it lost power as it tried to berth in Wellington yesterday.
The company said a 30-year-old electronic card that controlled the pitch of the propellers failed.
KiwiRail said the card had now been replaced.
A 6.30pm frieght-only sailing went ahead today and passenger sailings on the ferry would resume tomorrow morning.