Pain Before Gain as Commuters Brace for Railway Closure

One of the nation's oldest suburban railways will carry its final service before being absorbed by Australia's biggest public transport project.

The first line on the Sydney Metro to the city's northwest opened in 2019, followed by its driverless trains running under the city's iconic harbour to Sydenham in the city's southwest since August.

But further expansion southwest to Bankstown will come at the cost of a busy heavy-rail line that has been carrying passengers since 1895, when trips terminated a few stations earlier at Belmore.

"There will be long lines and delays, but in the end, this period of pain will be worth it," Transport Minister Jo Haylen said ahead of the line's closure for conversion to metro standards.

Trains from Bankstown will still shuttle commuters to Lidcombe, where passengers can connect to other lines, but those services will not begin for weeks.

"It's better than having no train at all ... even though it's a shuttle train," Restore Inner West Line convenor Roydon Ng told AAP.

But car dependency is likely to increase, creating more traffic for replacement buses to get caught in, he said.

The pink Southwest Link buses brought in to replace trains have already begun operating, despite the train line's closure being delayed by a dispute with the Rail, Tram, and Bus Union.

The union has objected to the closure and the Labor government following through with the conversion, which like much of the wider metro network was planned while the coalition was in office.

"The metro conversion is a bad policy decision that will haunt rail travel in Sydney's southwest for decades to come," it said.

Replacement bus services are free in recognition of the impact on passengers.

The conversion is expected to take 12 months but the transport minister has acknowledged it could take longer.

"There are always things that might be unexpected or things that you can't control," Haylen said.

"But also, this is a 130-year-old train line, and it is a complicated process," she said.

Barriers will be installed on platforms and on bridges over the rail corridor as part of the conversion for driverless trains.

Sydney Metro is the nation's biggest public transport project, comprising four lines, 46 stations and 113km of new rail.

The project also includes lines to the city's west and the under-construction Western Sydney Airport.

Another massive project, Melbourne's suburban rail loop, plans to use the same tunnel-boring machines that dug under Sydney Harbour for the metro.

The final train from Bankstown to Central leaves at 11:52 p.m. on Sept. 29, before the last service going the other way at 12:15 a.m. Sept. 30.