KiwiRail is to install about 300 railway sleepers made from recycled plastic bottles.
The company has ordered the plastic sleepers from a United States supplier.
Just over half will be for bridges and the rest for railway turnouts, which allow trains to be guided from one track to another.
Track engineering manager Mark Gullery says KiwiRail has gone with the black plastic product because they are looking to use alternatives to the traditional hardwood sleeper.
Mr Gullery says testing has shown they are just as good as their concrete counterpart and will not burn.
Canterbury University students will also put the sleepers through rigourous testing, he says.