A WERRIBEE woman says she feared for the lives of herself, her daughter and fellow passengers on a packed train travelling at full speed with an open carriage door in peak hour last week.

Heatherbelle Borysiewicz did not have much luck on Connex trains on Wednesday, with incidents on her trip into the city and then home later that afternoon.

The mature-age RMIT interior design student was travelling to class on Wednesday morning with her daughter when one of the automatic carriage doors failed to close between Newport and Spotswood.

"The train was packed, it was during peak hour. I thought the people could have fallen out because the door was open and [they could have] fallen to their deaths. It was just very dangerous," she told the Banner.

Connex spokesman John Rees said that investigations had shown a passenger running late for the train had forced the doors open, knocking them off their rollers.

"[That] explains why the doors were open," he said.

"Further inspection of all the doors on the train showed them to be working correctly, so the driver got them back on the rollers at Spotswood and they worked OK from there on."

However, he said investigations were continuing over what led the driver to believe he could proceed.

Later, Mrs Borysiewicz caught the 4.52pm Werribee train at Melbourne Central.

She was shaken when she stepped onto the platform at Werribee station, claiming the train was going too fast.

"I was really scared that the train would derail it was going that fast," she said.

"I looked around at the other people on the train, and they had looks on their faces like they were concerned about the speed the train was doing.

"It just lurched and swayed from side to side, that's how fast it was going."

Mrs Borysiewicz said there was a stretch in the journey where the train sped up, but that it had not increased speed once, but twice.

"I'm not sure if the train was running late or not, but it worries me that Connex might be putting passengers' safety at risk to avoid getting fines [from the State Government]."

Mr Rees said Mrs Borysiewicz had caught the express service, which was allowed to travel up to 115kmh after Newport.

However, he said the train did not always travel at this speed.

"The line is rated and tested and drivers trained to do the line speed," he said.

"Some customers may not have experienced their train travelling at this maximum speed and were therefore unused to the sensation. There was neither a safety or a speeding issue."

Mrs Borysiewicz travels on the line several times a week.