Closure of major Sydney train line to occur earlier than expected

More train pain is on the way for commuters in Sydney's south-west and it will arrive sooner than first expected as the government pushes ahead with the new Metro service.

The disruptions to the T3 Bankstown line between Bankstown and Sydenham will begin at the end of August to make way for conversion works to run driverless Metro trains.

The line will be on and off again until next year.

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It will be shut down for eight weeks of school holidays over spring, summer and next autumn on top of another seven weekend closures between now and May.

This is just the tip of the iceberg, with the real pain beginning mid-next year when a full-scale 12-month shutdown between Bankstown and Sydenham is needed to complete the work.

The South West Metro line is forecast to open in late 2025.

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It comes as the NSW government announced the project will cost an extra $1.1 billion to complete - along with the shutdowns.

Transport for NSW and Sydney Metro are developing a temporary transport plan to run during the shutdown.

There are expected to be "dedicated, frequent bus routes, including express services".

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