The rail lines to Australia's main coal terminal at Kooragang in Newcastle remained disrupted for six hours on 20 December after an environmental activist group blocked the lines, protesting against the Copenhagen climate agreement.
More than 40 members of the Rising Tide group chained themselves to the rail lines early in the morning, with some also chaining themselves to an 8,000t coal train outside the port.
Police intervened to break the protest up.
The activists were voicing concern over the failure of the Copenhagen climate change talks to produce a "just, effective and legally binding" treaty.
At the climate conference in Copenhagen, the world leaders have agreed to limit global warming to 2°C above pre-industrial levels, but with no binding emission targets.
Newcastle, north of Sydney, is the country's biggest coal export facility and ships nearly 100 million tonnes of coal 24 hours a day, mostly to Japan and Taiwan.
The group has warned of further protests.