It is hoped ground will be broken early next year on the first stage of a project aiming to provide a cycle trail link between Mosgiel and Dunedin.
Dunedin Tunnels Trail Trust trustee Gerard Hyland said he was optimistic volunteers would be setting to work on a trail through the Chain Hills tunnel, all things going well.
A Dunedin City Council working party investigating the possibility of creating a cycle trail that went through both the Caversham and Chain Hills tunnels had moved its focus to the 158m Chain Hills Tunnel this year, because that tunnel had less ''issues'' blocking its use, he said.
The plan was that the disused Chain Hills railway tunnel would be one stage of a proposed trail linking Wingatui and Burnside, which would later be extended to be a complete trail linking central Dunedin to Mosgiel via both tunnels.
Mr Hyland said the working party had been dissolved and had handed over the current stage of the project to a newly-formed project control group to continue activities on the ground, including beginning talks with private landowners at either end of the 148-year-old CHK tunnel, and with Kiwirail about easements for the trail.
After dealing with many obstacles since the first group was established informally to look into the idea in 2005, the group had recently had a ''major breakthrough'', he said.
Following the council's removal of gas vents in the tunnel, its classification as a ''confined space environment'', which meant anyone working inside it needed a special qualification and extra safety requirements needed to be followed, had been dropped by the Ministry of Business, Innovation and Employment.
That was such great news because it removed a lot of barriers to entry and work within the tunnels, he said. As soon as the easements were agreed, and the path of the track worked out, the volunteers could get straight in and start work.
First on the agenda would be working out what work needed to be done to build the trail.
The physical work would likely take part in stages, and include involve surface preparation, and brick repair and drainage in the tunnel.
The access from Gladstone Rd Nth to the western end of the tunnel, and from the eastern end down through the valley to the rail corridor, and along that to Abbotsford would be additional stages.
When done, the trail would essentially be a nearly flat link between Dunedin and the Taieri Plain, that otherwise required traverse of Lookout Pt and Saddle Hill, Mr Hyland said.
Earlier this year he said estimates of costs for the Chain Hills stage of the project ranged from ''several hundred thousand dollars'' to more than $2 million.
Last week Mr Hyland said the cost would need to be worked out after the easements were in place, then the question of raising the funds would be have to be addressed.
The Dunedin City Council has an agreement to maintain the track once it is built.
He expected the project control group would make a progress report to the appropriate council committee at the end of this year or early next year.
In the meantime, the group was aiming to achieve land arrangements with which all parties were happy,
so the trail could go through farmland.
Initial brief discussions had been had with the two landowners and Kiwirail.
''Once the easements are in place and all parties are happy we'll be starting to break ground, effectively.''
The mood was very hopeful, he said.
''It feels like we're staring to get a bit of traction after many, many years of reports and investigations and issues being raised, we're now at the point of actually getting down on to the ground and getting something positive achieved.''
