Australia's longest-ever grain train has rolled across north-western New South Wales carrying 5,000 tonnes of wheat.

Comprising five locomotives and 73 wagons stretching 1.3km (0.8 miles), the train left the town of Narrabri on Wednesday.

It later unloaded its cargo of wheat bound for markets in South East Asia at the port of Newcastle.

Drones shot video of the bright yellow train as it snaked its way across the Australian countryside.