Abbeyton Bridge, on the B966 just north of Fordoun, is threatening the region’s railway link with the south, with the potential for it to collapse onto the rails below.

The 170-year-old bridge was closed to vehicular traffic in July after inspections found serious failings in the structure, which continue to be monitored.

A specialist contractor has been brought in by Aberdeenshire Council and it will work alongside council engineers to dismantle the bridge over Christmas Day and Boxing Day, starting at 10pm on Christmas Eve – after the last train of the day.

Emergency measures were agreed by councillors last month to allow for the work to take place in the interest of safety.

The local authority’s infrastructure services committee heard an emergency closure of the railway could cost the council around £1-3 million per day to cover disruption to railway services using the line.

The cost of the demolition alone is expected to be in the region of £1m, over one third of the council’s £2.8m annual budget for bridges and other structures.

This will delay planned works on other bridges and structures around Aberdeenshire, which may deteriorate further in the interim.

No decision has been taken as to whether or not Abbeyton Bridge should be replaced.

The council said the primary focus is on carrying out the works necessary to protect the safety of rail users.

However, significant investment would be required to replace the bridge and that will have to be considered in the context of current budget provision.

Aberdeenshire Council’s bridges manager, Donald Macpherson, said: “The only way to remove the risk posed by this bridge to the railway line below is to remove the bridge itself, as it cannot be repaired. Given the potential financial implications an unplanned closure of the line would have, this has to take place on Christmas Day and Boxing Day, when no trains are scheduled to run.

“If all goes well the work will be completed by 5am on Thursday, December 27, in time for the railway returning to normal service.”

Earlier this month a local MP suggested that the British Army be drafted in to build a temporary bridge for cars affected by bridge’s closure.

Aberdeenshire Council said the cost of any proposed replacement bridge is likely to run into millions of pounds, and take several years to plan, therefore there is no financial provision for this within its current budgets.