Fifty old commuter train carriages are taking one final journey to Wellington's Southern Landfill over the next few weeks.
The carriages, each about 20m long and weighing about 25 tonnes, are being delivered by truck to the landfill where they are to be scrapped.
Metlink has been trying to sell the old carriages for reuse for years, said manager of rail operations Angus Gabara.
"Initially they were sold to a South African buyer, who took a first lot of 16 units [32 cars] to be reused in service in Africa. But the deal for the remaining 26 units officially fell through in late 2017. The units were re-tendered again earlier this year and the tender was won by Macaulay Metals to dispose of them," he said.
The Hungarian-built Ganz Mavag trains ran on Wellington's commuter lines from the early 1980s until they were replaced by a second order of Matangi trains in 2016.
"We undertook a detailed business case to determine if it was better to refurbish the Ganz Mavag trains, or buy new.
"This process determined the economic benefits for buying more Matangi trains to be considerably superior, which is why we have a full fleet of Matangi trains and retired the Ganz Mavag fleet."
The remaining carriages have been stripped by local company Macaulay Metals. The bogies and motors and other recoverable scrap will be separated from the units but the car body itself contains asbestos within the anti-drum coating inside the walls of the train.
"The cost of removing the anti-drumming coatings to salvage the scrap is too expensive," Gabara said.
"Asbestos is contained in the anti-drum coating and will remain undisturbed during the dismantling and transport to the Southern Land Fill."
The carriages will then be crushed and buried.
"Burying the carriages is the least expensive and safest way to dispose of the carriages because of the asbestos issue."
The whole operation is expected to take about a month to complete. One carriage has been gifted to the National Railway Museum in Christchurch.