Usage of the proposed trail extension for cycling and walking could be particularly high if "the Taieri Gorge trail corridor encompasses the most iconic heritage rail infrastructure and scenery", economist Benje Patterson said in his just-released report for the Otago Central Rail Trail Trust.
That would include crossing the Wingatui viaduct and several other bridges and railway tunnels.
It would also end the Taieri Gorge as a railway route — a contentious proposition when train services are part of Dunedin’s tourism product, including for thousands of passengers from cruise ships.
A compromise would allow trains from Dunedin to run as far as Hindon — as they typically do now — and part of the trail would be pushed out to run through bush to Outram, but this would result in "less opportunity for trail users to see and experience heritage infrastructure".
The Otago Central Rail Trail is a 152km ride or walk that follows the former railway line between Clyde and Middlemarch.
It has been a reliable visitor drawcard and the number of visits was estimated to be about 12,750 people in the 12 months to June 2023.
Mr Patterson said this generated a spend of about $25.9 million but little of this flowed through to Dunedin.
Many visitors flew into Queenstown, started their rail trail journey in Clyde, rode to Middlemarch and took a shuttle back to Queenstown.
Rail trail visitors stayed for 5.7 nights on average in the area, spending on average $414 a day, Mr Patterson said.
Extending the trail past Middlemarch might lift the annual spend of trail visitors by between $6.9m and $11.4m, he said in the report.
The two trail extension options would each add about 60km, which is achievable for a day trip, particularly for people riding electric bikes.
It was likely day-trippers would make Dunedin their holiday base, "meaning that much of the additional spending attributable to the Taieri Gorge extension is likely to primarily accrue to businesses within Dunedin", Mr Patterson said.
"Riders traversing the entire length of the Otago Central Rail Trail are also likely to stay at least an extra night in the Dunedin area to give themselves time to pedal the Taieri Gorge extension."
Mr Patterson modelled two scenarios — high and low usage of an extension.
The high scenario could have 39,306 visits a year of the gorge extension, comprising 11,187 from people completing the whole trail, 18,470 visitors doing just the Taieri Gorge segment and 9649 locals doing just the gorge section.
This would rely on the gorge section being considered a "destination ride", which would require riders to enjoy an exceptional experience.
The low scenario might still bring 23,009 visits to the gorge extension, comprising 8949 from people completing the entire rail trail, 9235 visitors for just the Taieri Gorge segment and 4825 locals to the gorge section only.
The Dunedin City Council has signalled it intends to facilitate a train service between Dunedin and Middlemarch, but a multimillion-dollar deferred maintenance bill for the Taieri Gorge tracks would need to be faced, much of it north of Hindon.
Mr Patterson’s report for the rail trail trust did not analyse benefits of train operations. A previous report from him identified $24m of spending by Dunedin Railways passengers in the city in the 2019 financial year, including more than $17m on non-rail expenditure.
Economic benefits from a trail extension would initially be focused on Dunedin, but would also provide a lift for Middlemarch and be "diffused into smaller communities", he said in his latest report.
"Given these potential economic opportunities from an alternative use of the Taieri Gorge railway corridor as a trail for biking or walking, it is important that decision-makers factor this into any decision-making process regarding future investment into the Taieri Gorge railway."
