The bitter dispute between the NSW government and the rail union appears to be at a critical point after two days of strikes in a week, as negotiations continue over a billion-dollar offer.

Sydney commuters battled cancelled services and delayed trains on Thursday, as workers from the Rail, Tram and Bus Union (RTBU) walked off the job at City Circle and Redfern stations, and suburban trains operated on a reduced timetable.

The strike came despite the offer from the NSW government to make long-awaited changes to a fleet of Korean-built intercity trains, which the union believes are not safe to operate.

Treasurer Matt Kean says the government’s deed, delivered on Wednesday, amounts to $1 billion worth of modifications.

Mr Kean maintains the Korean-built fleet is safe, but said the government was committed to ending the feud with the union.

“A billion dollars, to rip out CCTV cameras from the trains, to remove sensor technology, to modify platforms, to store the trains – to do a whole range of things,” Mr Kean told media on Thursday.

RTBU secretary Alex Claassens said he received the deed 10 minutes before Employee Relations Minister Damien Tudehope held a Wednesday press conference calling for an end to the industrial action, despite conceding an agreement had not yet been signed by either party.

“That was never going to happen,” Mr Claassens told reporters on Thursday.

‘I think it is doable’

He said it would take at least 48 hours for union delegates to review and vote on the deed, and timetable-planning for the network would take just as long.

However, Mr Claassens said the deed was better than the one the union received last week.

“I think it is doable,” he said.

Negotiations over the deed were ongoing on Thursday evening, with tweaks still being sent back and forth for approval.

It could be enough to head off a ban on operating foreign-built trains – which make up the bulk of the network – next Wednesday, the final day of the union’s planned August industrial action.

The industrial action comes two days after a chaotic Tuesday on Sydney’s rail network, when services on the T1, T7 and T9 lines were affected, and the T5 line was prevented from operating.

The union says the NSW rail network is not designed to run driverless or guardless trains in the same way as the Sydney Metro, where platforms are separated from approaching and departing trains.

The new trains use CCTV to monitor platforms, and the union wants the screens moved out of the driver’s field of view to prevent distraction.

Guards on the train should monitor platforms in person, as well as using the cameras, the union says.

Mr Kean said the trains have been deemed safe by the Office of the National Rail Safety Regulator, but the union disagrees.

“All the rail regulator does is ensure that rail operators follow the correct procedures,” the RTBU said.

“It does not determine whether any component of the trains, including how they are operated, are safe.”

The RTBU is expected to provide an update on Friday.