Freight rail operator Aurizon is shedding about 300 jobs in response to weak coal prices.
The company plans to cut approximately 180 workers in train crews, yard operations, maintenance and infrastructure production, plus about 120 middle and senior managers.
In an announcement after the close of ASX trading on Thursday, Aurizon said it is also writing down the value of its rolling stock - carriages and locomotives - by $29 million, before tax, taking total pre-tax writedowns on those assets to $177 million in the 2015/16 financial year.
"Clearly we're operating in a tough and volatile market with lower growth conditions for our customers," chief executive Lance Hockridge said.
"More than ever in this environment, we are targeting further reductions in our cost base and finding new ways to drive asset and labour productivity.
"Work is underway across the company, in reducing management roles, in driving down corporate and support costs and ensuring workforce numbers are aligned to forecast customer demand."
Aurizon has also announced an additional $73 million impairment against its investment in Aquila Resources, due to that company's deferral of the development of its coal assets.
Aurizon made a loss of $108 million in the first half of 2015/16 mainly due to impairments on its stake in Aquila, which it acquired in a joint deal with China's Baosteel in 2014.
The latest round of impairments will be recognised in the company's 2015/16 annual financial results, to be released in August.