Coal train activist's sanity questioned

A Queensland magistrate has questioned an anti-coal activist's sanity after he stepped in front of a moving train to protest against climate change.

The five-hour protest on an Aurizon coal train in Brisbane caused rail delays and cancellations costing the freight company about $1.3 million.

Magistrate Walt Ehrich granted Jaxom Kerlin, 18, bail in the Brisbane Magistrate's Court on Saturday.

But not before he questioned the young man's mental health.

"This sort of behaviour doesn't sound like a person who is quite sane," Magistrate Ehrich said.

Police prosecutor Senior Sergeant Bill Heasley told the court Kerlin's actions held up five coal trains travelling to the Port of Brisbane for 14 hours at a cost of $90,000 per hour.

Another three trains were cancelled, with the total cost to the freight company, Aurizon, likely to be about $1.3 million.

"It would appear the behaviour is motivated by a certain ideology - concern for the environment," Snr Sgt Heasley said.

Kerlin was charged with obstructing a railway, trespass and obstructing police after he was coaxed from the carriage by officers about 7.45pm on Thursday.

His protest began about 2.30pm when a group of activists stepped onto the tracks near the port at Wynnum.

The driver was forced to apply the emergency brakes to stop the moving train from hitting the protestors.

Kerlin was the only activist to climb up onto the train.

He was granted bail by Magistrate Ehrich on condition he not engage in any protests and report to police twice per week.

Outside court, about a dozen climate and anti-coal protestors gathered to support Kerlin.

One protestor brandishing a banner saying "climate emergency" was arrested by police.

The woman attempted to display the banner in front of TV cameras filming the family of a man accused of murdering Dr Luping Zeng as they left court.

Kerlin is due to reappear in the same court on May 1.

A second activist is also due to front court following another protest against coal mining in Wynnum.

The woman chained herself to a concrete-filled 44-gallon drum placed on the same railway line about 2am on Friday.

The woman remained locked to the drum until she released herself and surrendered to police about 7am.

Queensland Ambulance then took the woman to the Princess Alexandra Hospital suffering Hypothermia.

The woman has also been charged with obstructing the railway, trespass and obstructing police.

She is due to appear in the Wynnum Magistrate's Court on May 7.