The Queensland government approved three leases in April for Indian company Adani to build the coal mine and rail project in central Queensland.
State development minister Anthony Lynham said the approval was for about 31.5km of permanent rail line, as well as a temporary construction camp with up to 300 beds.
"This is another key milestone for the project, which Adani has confirmed it will start construction on next year," Lynham said.
The project already has "all primary approvals as well as prescribed project and critical infrastructure project status in place to reduce red tape", the Queensland government said.
The rail section approved this week will form part of a 389 kilometre standard gauge, heavy haul railway line from the mine in the Galilee Basin to the coal export Port of Abbot Point, Queensland.