Auckland Transport is defending a decision to scrap its Waitakere train service.

The decision has been slammed by some train users, who boarded the service this morning dressed as mourners and carrying a coffin.

But the agency says it won't change its mind.

AT Metro acting manager Colin Homan says an electric train runs from the CBD to Swanson, and a separate diesel shuttle to Waitakere doesn't make sense.

"If there was any delays, it would result in both the diesel rail to Waitakere and the electric Swanson to Britomart services being compromised."

The protesters, who dressed up as ghouls and grim reapers, from from the Public Transport Users Association.

They led a polite and quiet vigil, apologising to one man for getting in his way.

Spokesperson Jon Reeves says the board of Auckland Transport is out of step with public opinion, and needs to listen to what the community wants.

No trains to Kumeu

Commuters in north-west Auckland may have to give up on their dreams of taking the train to work.

Auckland Transport is rejecting calls for a daily commuter rail service for Helensville and Kumeu, using existing stations on the Northern Line.

The Public Transport Users Association and some locals say it would serve growing populations and ease peak-hour traffic.

But Colin Homan says bus journeys are cheaper and take less time.

"The distance from CBD to Huapai by train is 41 kilometres, whereas by road it's 28 kilometres."