One month after the Kaikoura rail line reopened following earthquake repairs, Mother Nature has shut the route down again.
Last November's 7.8-magnitude earthquake near Kaikoura closed the line, when it was buried by more than 100 slips and landslides.
Another 60 bridges along the line were also damaged and had to be repaired.
This time, the cause of the closure is unusually heavy rainfall in Canterbury in September and October.
The rain has caused 31 slips, including three major falls, which have brought rubble down onto the main north freight line and the nearby coastal road.
"As a result, the main north line has closed temporarily, while we work to make repairs and add resilience ahead of the peak freight period," KiwiRail acting chief executive David Gordon said.
He expects rail services to begin operating again at the end of the month. The line only reopened in September, after suffering major earthquake damage.
Its reopening allowed limited freight train services to run at night, while workers continued to repair the track during the day. The repairs were the country's largest rail rebuild since World War II.
"The impact of the rain has devastated the teams who worked so hard to get the main north line running again,'' Mr Gordon said.
The limited number of freight trains that were able to run at night over the past month were estimated to have taken about 2000 trucks off inland Canterbury roads.
Mr Gordon regretted these trucks would now be forced back onto local roads, until the line reopens.