Tanya Day, 55, died from a brain haemorrhage in December 2017 after being removed from the Castlemaine service.

"It was the most low key arrest I've ever done," Senior Constable Stephen Thomas told a coronial inquest on Wednesday.

"I didn't formally say, 'you are now under arrest', I just expressed I wanted her to come with me and I guess by compelling her to come with me that's a form of arrest."

Despite finding she was intoxicated the police officer said Ms Day didn't appear to be unruly.

"I didn't see what I would call unruly behaviour," Snr Const Thomas said.

He did consider leaving her on the train but decided not to because he was worried he'd be held responsible if something did happen to Ms Day.

Once she was in custody, police didn't go inside her cell until she was due to be released that night.

She died in hospital 17 days later from brain injuries.

Coroner Caitlin English is examining whether racism contributed to Ms Day's death.

The court has also been shown CCTV footage collected from the train station platform, which shows V/Line staff and police entering the train and re-emerging with Ms Day, then interacting with her as she briefly sat on a bench before the group moved to the car park.

EARLIER: Police who arrested an Aboriginal woman before she died in custody say they did it for her own safety.

Tanya Day, 55, died from a brain haemorrhage in December 2017 after being taken off a train in regional Victoria because she was drunk.

Senior Constable Stephen Thomas helped escort her from the carriage at Castlemaine after rail staff called to say an unruly, intoxicated Aboriginal woman was travelling without a ticket.

"Other people on the train had a look of disgust and it was obvious to me she made other people on the train feel uncomfortable," Sen Const Thomas told a Melbourne inquest into Ms Day's death on Tuesday.

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He said she smelled strongly of alcohol and her words were "almost unintelligible".

"I said to her that she had to come with us and I told her that we would try to look after her and get someone to come and pick her up."

As police were taking her away, she told them "here we go again, it's like this is it", Sen Const Thomas said.

"I said to her it wasn't like that and that we were trying to look after her."

Police didn't go inside her cell until she was due to be released that night. She died in hospital 17 days later.

Coroner Caitlin English is examining whether racism contributed to Ms Day's death.

Train conductor Shaun Irvine said he found Ms Day sleeping on the seats and decided she was unruly after she couldn't provide relevant answers to his questions.

He wanted police to come because he was afraid she'd fall and hurt herself if she left the train on her own, and denied he would have acted differently if the passenger had been white.

Police are expected to continue giving evidence at Ms Day's inquest on Wednesday.

Australian Associated Press