An eco-friendly pressure group demonstrated its determination to plough on with plans to complete a leisure track yesterday when it opened up a new section of the Great Northern Trail at Queensbury.

It made the move even though things have not been running entirely smoothly for Sustrans, whose ambition is to link Cullingworth with Queensbury along the defunct rail line.

Holding up progress is a legal dispute between Bradford Council and a plant hire business boss who uses land next to the line at Queensbury.

As the opening ceremony took place, a City Hall spokesman admitted that no progress had been made and there was, so far, no agreement.

It means the new section covers only about three-quarters of a mile from Queensbury to Cockin Lane, just outside the village.

It leaves the magnificent 20-barrel-arched, 100-feet-high Thornton viaduct, restored by Sustrans last year, marooned between Cockin Lane and Headley Lane. Standing in between is the disputed site used by Philip Summers.

The route however does include the landmark Queensbury Triangle railway station site, the hub of the former Great Northern Railway.

Jeff McQuillan, chairman of the Great Northern Trail Forum, said: "Bradford Council is involved in attempting to acquire the land - we have to wait.

"What we have been able to do is finish this part of the route as far as Cockin Lane, up to Mr Summer's land.

"It now makes it more urgent that negotiations are completed. We are aiming to get to Thornton and have repaired the viaduct in preparation.

"Thankfully, we have settled agreements with other landowners and I would especially like to thank Neil and Tina Crossley, the owners of this section, who have been very co-operative. Without that we would not have been able to open this section."

Agreements had also been settled with landowners beyond Headley Lane, he added.

"Thornton people across the valley are itching to get using this route but they will have to wait a little longer."

The section had been completed in record time - about eight weeks - thanks to the co-operation of the landowners and funding from Bradford Council and Natural England.

About 50 people, including horse riders, walkers and cyclists turned up to see the section officially opened, timed also to coincide with National Bike Week.

Special guest was John Grimshaw, founder of Sustrans, which is celebrating its 30 anniversary, who had travelled from Bristol.

He was joined by five year-old Rory Kunz, a pupil at Crossflatts School, Bingley and the youngest volunteer ranger.

Rory, whose dad Richard is also a ranger, has been awarded a medal for his efforts to encourage other children to walk and cycle to school.

He said: "I like helping my dad - we do litter picking and put up signs.

"I helped him arrange an Easter Egg hunt and a Halloween trail. And I like riding my bike and walking the trail with him."

Among the first to "christen" the route was seven-year-old rider Hazel Greenwood on her pony Sparkie accompanied on Dixie by her grandmother, Ruth Neen, of John Street, Clayton.

Mrs Neen said: "This is absolutely fabulous. It is a great way to use the old track especially for young riders like Hazel who can't use the road."

And cyclist and runner Tony Smith, 64, of Clayton, said: "Now that this section is open it is vital to get the rest done."

Sustrans' aim is to continue to build the route to Thornton viaduct which will link Thornton Primary School and the village of Thornton.

Eventually it will run on as far as Harecroft where the first section to be completed two years ago arrives from Cullingworth.

David Hall, Yorkshire Regional Manager of Sustrans, said: "Slowly but surely we are piecing together a tremendous amenity for public health and enjoyment.

"The task ahead now is to continue the route through to Thornton and eventually to connect up with the existing route into Cullingworth."

Meanwhile, railway expert Jan Rapacz, who was also present, is working with fellow railway buff Alan Whitaker on a history of the line.

"It was a very unusual line and this section was occupied by the Queensbury Triangle where the route from Bradford, Halifax and Keighley met," he said.

"It was one of the most heavily-engineered lines and included the construction of Queensbury tunnel, the portal of which can still be seen."

The aim was that the history would also act as a guide to people using the trail, he added.

Long term, Sustrans aim to open up the full six miles of the old rail line which was built between 1876 and 1884.

It was characterised by deep cuttings, high embankments, tunnels and the huge viaducts and was known by locomotive crews as the "Alpine Route".

It was closed to passenger traffic in 1955 and to goods trains in 1960.

The first phase of the new track between Cullingworth and Harecroft and containing both Hewenden and Cullingworth viaducts, was opened in May 2005.

It was followed by the restoration of Thornton viaduct which sweeps below the village, crossing Lower Kipping Lane and is a grade 11-listed building. The 300-metre-long structure is particularly unusual because of its "S" shape.

The Queensbury stage is part of the second phase of the work, the final task being eventually to complete the middle section.