They are the "forgotten" commuters of Sydney - set to have their direct train service to the CBD taken away from them.

While the state government has been championing the construction of the Sydney Rapid Transit Network, it has been quieter on the topic of those who could be left with a more difficult journey.

Thousands of people who travel on the Bankstown Line west of Bankstown Station will need to change trains at least once to get to or from the city under the government's plans for a new metro line.

This is because the existing Bankstown line between Bankstown and Sydenham will be converted to run automated single-deck trains, linking to Chatswood through a second harbour crossing.