Trainloads of recycled ballast have arrived as workers prepare to link the Oxford-Bicester line with the Chiltern Mainline.
A new embankment will be built using 80,000 tonnes of recycled stone.
Chiltern Railways said the decision to deliver the ballast by rail will save 10,000 return trips by HGV.
Chief project engineer Stephen Barker said: “Our impact on the environment is a key consideration as we construct our new line to London.
“For delivery of these materials, we have carefully assessed how to minimise the impact on both local residents and the environment.”
Construction of the rail link is due to start soon.