Protesters stop coal train in Brisbane

One protester is in custody and another was taken to hospital after activists stepped in front of a moving coal train headed for the Port of Brisbane.

The train driver was forced to slam on the emergency brakes after a group of protesters climbed onto the freight tracks in Wynnum on Thursday afternoon, police say.

"Then three men approached the carriages (and) one of them got up onto the carriage ... the man wouldn't come down," a police spokesman told AAP on Friday.

Officers coaxed him down about 7.45pm and he was charged with obstructing the railway, trespass and obstructing police.

He remains in custody and will appear in the Cleveland Magistrate's Court on Saturday.

About 2am on Friday, a woman activist chained herself to a concrete-filled 44-gallon drum placed on the same railway line in Wynnum West.

"She's sat on the tracks and locked herself on," the spokesman said.

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

"She had a low body temperature so Queensland Ambulance took her to the Princess Alexandra Hospital."

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

She was bailed to appear in the Wynnum Magistrate's Court on May 7.

No train was involved in the second incident.

Extinction Rebellion activist Emma Dorge said the group was protesting the lack of action to the global climate crisis in Australia.

"We can't wait anymore, we're taking direct action so people understand the danger the planet is in," she told AAP.