According to Regional Rail Revival's director Mark Havryluk, a planned construction blitz for late August has been replaced with night works - that means passengers won't have to take coaches for five days, and instead, only certain late night services will be affected.

"In June and July, when we had a construction blitz over a two week period, we were able to do more work than planned," he said.

"There'll still need to be a couple more periods, but that'll be when trains aren't running at night.

"We've been carefully planning our work, and the key requirement for us, at the top of our mind, is to minimise disruption as best we can."

Major station works, including the second platforms at Wendouree, Ballan, and Bacchus Marsh, are well under way, while the pedestrian overpass at Wendouree station should be installed before the end of August.

The new passing loops, which will improve congestion, are almost finished at Ballan, Millbrook, and Warrenheip.

"There are a couple of smaller tie-ins that need to be completed, but the majority has been completed," Mr Havryluk said.

"We're also undertaking signalling works at the track associated with the passing loops - when a passenger's on a train, they can see ... the signals and trenching to get cables to those signals which is under way."

Mr Havryluk denied earlier claims the project had been delayed - he said a "misalignment" had occurred between budget papers and parliamentary estimates, but confirmed works should be completed on schedule.

"We're focused on targeting getting all the stations completed and major construction work done by the end of year," he said.

"With any major construction project, there's a lot of work to be done."

Earlier, concerns were raised about the condition of roads surrounding Ballan station during construction, but Mr Havryluk said they would be returned to their original condition.

"We're working closely with councils to ensure that when it's completed, that where the project has had a footprint, any existing assets, we'll bring them back into the condition we found them in," he said.

Following the end of construction, there will be a period of commissioning and safety testing on the new parts of the line, which should be completed early next year.

The Bungaree rail loop, which goes past Gordon, will be decommissioned and removed after construction, which will include removing five level crossings and 12 kilometres of track.

Mr Havryluk said the statistics involved in construction were huge - workers have completed more than a million hours installing 30 kilometres of track and 42,000 concrete sleepers.

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