South Australian tram and train drivers fear their jobs will become insecure when the state's rail network is privatised.
Hundreds of people gathered on the steps of parliament on Sunday to oppose the Liberal government's plans.
One train driver, who has worked in SA transport for 26 years, said safety standards will be dropped and jobs will become insecure under the Liberals.
"We've seen it happen 20 years ago when they privatised the buses," the worker said.
Fearing government reprimand, he chose to speak under the condition of anonymity.
"A lot of us, we actually strive to come and work in this industry, one of the reasons because it was also a government job," he told AAP.
"We thought that would be secure and we would be able to spend the rest of our lives as a government worker."
Another worker said a private company will just want to make a profit and send the money overseas.
"That's going to cover jobs, wages and probably ticket prices," he said.
They both said the government still has not properly explained how privatisation will affect them directly.
Opposition leader Peter Malinauskas spoke to the crowd, calling privatisation a "right-wing ideology".
At the state Labor convention on Saturday, Mr Malinauskas promised to return the rail network into public hands, should the party be elected in 2022.