A report from 2022 released by the Dunedin City Council this week concluded passenger rail services would be able to run between Dunedin and Middlemarch.
Infrastructure and engineering consultant Holmes identified no urgent or immediate major maintenance or remedial works that would impact on running services over bridges or through tunnels.
Tourism train services have been wound back to some extent since the Covid-19 pandemic and regular services have not run regularly at the Middlemarch end since 2019.
It is expected an upgrade of at least $20 million would be needed for a maintenance catch-up.
However, the council took issue with claims parts of the corridor might be unsafe.
Retired engineer Kevin Phillips had highlighted a series of concerns last week during a Mosgiel-Taieri Community Board meeting.
Among his concerns were the impact of 56-foot carriages on the line and what he said was the poor condition of the track from North Taieri to Middlemarch.
"My concern is I don’t want it on my conscience if or maybe when something happens", he said.
An independent audit, conducted in November 2022 by Holmes, looked at the condition of the Taieri Gorge track, including bridges and tunnels.
Bridges and tunnels were generally in a satisfactory condition, the consultant said.
However, Holmes agreed with previous recommendations about replacing rail beams and corbels, or brackets, which needed urgent attention.
Dunedin City Holdings Ltd (DCHL), which owns Dunedin Railways, provided an update about that this week.
Dunedin Railways engaged a consultant civil, structural and corrosion engineer in November last year to independently assess the safety of the Wingatui Viaduct bridge, a DCHL spokesman said.
"Five of the eight spans have had their wooden rail beams replaced with steel, and the consulting engineer has approved this replacement design and continues to monitor the bridge", he said.
"The remaining rail beams have also been strengthened and will be replaced within the next three years.
"Corbels also continue to be monitored and will be replaced between July 2024 and June 2025."
Mr Phillips highlighted an area of subsidence.
Dunedin Railways was monitoring this closely, the spokesman said.
This included "tilt sensors", a surveillance camera and an alert-monitoring system providing real-time warnings when rain, wind or rail temperature were outside set specifications.
"As a result, we are confident the Taieri Gorge line remains safe and well-managed."
Holmes identified significant work that needed to be done.
This included taking steps to prevent corrosion, such as patch-painting.
"It is recommended that individual asset management plans be developed for the major bridges, which would provide the necessary evidence for developing a more accurate long-term investment programme."
