GB Railfreight (GBRf) has extended its contract to transport materials for Petrochem Carless to another five years.
GBRf is expected to haul gas condensate from North Walsham to Harwich and mud oil from Harwich to Aberdeen.
The UK-based freight hauler said it will move between one and five loaded trains per week.
It is also expected to work around two weeks notice for the number of trains moved.
GBRf is a specialist rail freight company operating intermodal and bulk traffic services in commodities.