The Bankstown train line in Sydney's west will be closed for between three and six months to allow it to be converted to carry single-deck metro carriages, the state government has confirmed.
"At the end of the day we have to do this – we have no option," Transport Minister Andrew Constance said on Thursday.
More NSW News Videos
Sydney Metro to deliver new stations
New rail stations will be built at Crows Nest, Victoria Cross, Central, Waterloo, Martin Place, Pitt St and Barangaroo under the Sydney Metro rail project.
"We're seeing patronage growth on the existing network at the moment of almost 10 per cent."
Mr Constance said the temporary closure from about the end of 2023 was needed because much of the construction could only be carried out once the existing trains stopped operating on the line.
![NSW Transport Minister Andrew Constance says there is no option but to temporarily close the train line.](/web/20170217130046im_/http://www.smh.com.au/content/dam/images/g/t/f/l/j/v/image.related.articleLeadwide.620x349.gue5ip.png/1487226914392.jpg)
"We acknowledge that there will be a period of disruption during the later stages of this project, but we have an expectation by working with industry that we can minimise that," he said,
"We are obviously aiming for three months or better, depending on how the building of the metro system can take place."
Significant preliminary work will also be undertaken during quieter times of the year such as weekends and school holidays.
Buses were the most likely alternative transport for commuters during the closure.
Mr Constance said about 30 per cent of people who travelled on the Bankstown line did not travel outside the rail corridor, which meant data from the Opal ticketing system could be used to decide on the best alternative transport.
All 11 stations between Sydenham and Bankstown will be renovated to include lifts, level platforms and screen safety doors.
Sydney Metro project director Rodd Staples said every station on the Bankstown Line would remain at its existing location but some platforms and entrances would be shifted.
About five residential properties at Sydenham would need to be acquired for the conversion of the line, as well as a small number of commercial leases.
"We are in the process of engaging with all of those property owners at the moment," he said.
The first single-deck trains are due to begin running on the converted Bankstown line in 2024, which will form part of stage two of the metro railway that continues on from Sydenham to the central business district and Chatswood.
Construction is starting this year on the Chatswood-to-Sydenham component of the line, and will require the demolition of 19 towers – some of which are as high as 22 storeys high – in Sydney's CBD.
An existing line between Epping and Chatswood in Sydney's north will also be closed for seven months from late next year to allow for the completion of the first stage of the $20 billion project.
The first section of the new line from Rouse Hill in the northwest to Chatswood is scheduled to be opened in 2019, the same year as the next state election.