The railway runs alongside the River Dee

The contractor in charge of the operation, George Law Ltd, handed the track bed across the viaduct back to the railway a week early, in time for the Easter break.

The viaduct - which has carried trains for over 130 years - is just a mile and a half away from Llangollen and is a crucial part of the heritage railway line.

Dave Owen, Chief Engineer and Director of Llangollen Railway said: "Due to the age of the structure of the viaduct water was passing through and washing mortar out, so it was slowly becoming unsafe.

"We're extremely pleased the work has finished ahead of schedule.

However, although trains can cross the viaduct, works to complete the repairs and to reinstate the platform extension for Berwyn Station, are expected to continue until July.

Services from Llangollen to Carrog in the Vale of Clwyd resume on 23 March.

Railway spokesman, Frank Spence said: "It is clear we took the right decision because to have delayed the work for a further season would have caused the costs to escalate."

The donation of £150,000 from the anonymous benefactor has allowed the whole process to go ahead

Dave Owen, Chief Engineer Llangollen Railway

But the railway trust says contributions are still urgently needed for the repair works to the viaduct.

Earlier this month, an anonymous benefactor stepped in to help Llangollen Railway Trust's appeal to raise cash for the repair and renovation work.

The trust were offered an interest free loan of up to £150,000 to be paid back over five years.

Mr Owen said: "The donation of £150,000 from the anonymous benefactor has allowed the whole process to go ahead."

Money for the project will also be received through Objective One, a European fund to help regenerate parts of Wales.

The project funding will allow the track to be removed over the viaduct, the replacement of the waterproof membrane, which protects the viaduct, and the stabilising of the structure.

The railway, which closed to passenger traffic in 1965 and to goods in 1968, was started up again in 1975 by a group of train enthusiasts.