Lack of certainty about long-term plans for Dunedin Railways was cited as the reason the temporary arrangement needed to carry on for at least another 18 months.
Consent was granted for the structure to remain until the start of June 2026, if needed.
The consented structure was described as a temporary scaffold and shrink-wrap over two spur lines next to the station’s southern platform.
"The extension is required because the principal shareholder of Dunedin Railways Ltd (being the Dunedin City Council) has yet to decide on the long-term future of the company and its assets", a planning report said.
"While the long-term future of the company is undecided, it is unable to make any long-term commitment about its repairs and maintenance facilities.
"The previously authorised temporary structure remains the most practical and cost-effective option for carrying out repairs and maintenance to locomotives and rolling stock until final decisions on the future of the company are made."
The temporary structure was initially granted approval in January 2022 for 12 months.
It then gained consent for a further year, expiring at the end of last year.
It was argued last month another extension would be needed.
