But that decision failed to take into account the sudden housing boom in the area, the Public Transport Users Association says.
According to Auckland Transport's own reports, in the next 30 years new urban areas totalling two-thirds the size of Hamilton will be developed in West Auckland, including about 30,000 new homes, 13,000 new jobs and 75,000 more people.
But some of the area is currently serviced only by buses, which get stuck in the congestion - the 060 bus departing Huapai at 6.30am arrives in the CBD at 8.33am.
The association believes its proposed rail shuttle, dubbed the Western Connector, will take 75 minutes.
Chairwoman Christine Rose said the train would use the existing track and stations at Huapai and Waitakere and a few of the refurbished but unused diesel trains to create a congestion-free commuter service linking with the electrified network at Swanson.
The Waitakere station received a $1.6 million upgrade to build park-and-ride facilities in 2013 but the temporary Huapai station hasn't been used since 2009 and would need an upgrade.
The association's modelling estimated the service would cost ratepayers about $1.5 million a year to operate without factoring in fare revenue.
"We've got this simple transport solution there with everything in place; it's just lacking a bit of bureaucratic and political will," Ms Rose said.
During a comprehensive consultation in Auckland's three key growth areas - south, north and the northwest - residents were asked for their views on how the public transport network could be improved. The reintroduction of a commuter train was the most frequently mentioned improvement in the Transport for Future Urban Growth consultation.
Auckland Transport's public transport network manager, Anthony Cross, said the biggest issue with the Western Connector proposal was "the cost relative to the number of people likely to use it".
Mr Cross said Transport for Future Urban Growth was assessing every option and so rail might be a part of it but "it's not a priority right now".
The agency is calling tenders for its new bus network in the area, which is going to be rolled out next year.
Another spokesman later added: "Auckland Transport is exploring a number of [bus and rail] options, including bus lanes, and different rail options including ... a diesel shuttle, electric trains with and without double tracking."