The UK's highest railway is set to be shut for safety reasons until at least mid-October - a month-and-a-half later than first expected.

The Scottish Government economic development agency Highlands and Islands Enterprise took the decision to withdraw the Cairngorm funicular railway from service on August 25 while a series of 'snagging' works were carried out.

It was first expected to be back in action at the start of September after it was hoped the works would be completed "relatively quickly".

But on September 6, it emerged that it was not expected to be back up and running until the end of the month.

Now the agency says the scale and complexity of the project, which includes continuous testing to ensure public safety, has led it to revise its schedule to complete the job to mid-October.

The decision to close the railway came after the leading Scottish Government economic development agency settled a court action against constructors and designers over structural problems. HIE said two weeks ago that it had received £11m after settling the court action.

READ MORE: Scot gov agency sues creators of shut Cairngorm railway for £14.5m

It had been pursuing a £14.5m claim against the company that owns Morrisons Construction and the civil and structural engineers for the scheme.

The Herald: The agency made claims over defects in the design and construction of the railway and breaches of contracts which emerged after the funicular was forced to shut five years ago.

The crucial funicular, which was opened in 2001 and connects a base station with a restaurant and a ski area 1,097m (3,599ft) up Cairn Gorm mountain near Aviemore, was closed in September, 2018 due to structural issues.

An engineering report from July 2018 noted that the structure's condition for it's age was "disappointing" with various defects identified. A second report commissioned by HIE confirmed that work was needed to strengthen the railway's piers, beams and foundations.

Balfour Beatty was appointed  in 2020 to reinstate the railway by 2022 in a contract which also covered other works to turn the Highlands peak into a year-round tourist destination.

HIE had at one point included a provision of £14.3m for the cost of reinstating the funicular.

It finally came back into action in January after a four-year hiatus and after a programme of works to strengthen the viaduct that supports the railway track.

HIE said a 12-month snagging and inspection programme has been running since the relaunch, "as is usual practice with complex engineering projects".

The latest disruption came following an inspection that showed that some of the ‘scarf joint assemblies’ that link the beams at the top of the piers did not meet the required tension.

An HIE spokesman said: “We recognise that this will be disappointing news for visitors to Cairngorm Mountain.

“Safety has to be the first priority and it’s vital that the snagging works are not only implemented effectively but also subject to rigorous testing, and these are jobs that can’t be rushed.

“The teams are working hard, seven days a week, to move the project along at pace and bring the funicular back safely into service at the earliest opportunity.

“Based on the experience we’ve gained since these works began a few weeks ago, we now believe mid-October is a realistic target date to work towards.”

The Herald: A hiker and their dog walking towards Coire an Lochain in the Cairngorms, Scottish HighlandsThe Cairngorms are a major Scottish tourism attraction and centre for recreation with downhill hillwalking and rock climbing a major draw for the 1.92m who visit the national park every year from around the world.

Skiing is seen as vital to the growth of the local area and led to the development of accommodation and other visitor attractions.

News of the long-running case emerged in 2021 when it was revealed that ministers had to refund part of an EU grant for the original Cairngorm funicular because of discrepancies in the way it tendered for the work as costs shot up.

As of the end of last year the cost to the taxpayer of funicular had soared to nearly £52m - with the costs of crucial repairs rising by 56% from £16.16m to £25m.

The faults were discovered after the costs of building the funicular spiralled from £14.8m to £26.75m.

Calls were made for a public inquiry into the management of the Cairngorm funicular.

A £14.5m claim was made against the now owners of Morrison Construction, Galliford Try Infrastructure Limited and Inverness-based AF Cruden Associates Limited, the civil and structural engineers for the scheme which had been taken over by Glasgow-based Arch Henderson.

The case was due to be dealt with in a proof hearing at the beginning of August.

But HIE confirmed that it had reached an out-of-court settlement for £11m - £3.5m less than the original claim.

HIE, which also owns the ski centre, secured planning permission for repairs from the Cairngorm National Park Authority in 2020 and Scottish government funding.

HIE said that while the works continue, Cairngorm Mountain remains open.