More than 1,500t of stone has been used to create a temporary dam in the River Clyde to allow repairs to a rail line damaged by recent flooding.
The dam is allowing engineers access to the base of a viaduct pier on the West Coast Mainline.
Large sections of the stone foundations for the pier at Lamington were washed away by floodwater during Storm Frank this month.
Engineers were due to pump 150t of quick-setting concrete into the void this weekend to recreate the pier base before starting work on the track above.
It is hoped the line will be reopened to passengers at this point on 1 February.
Network Rail managing director for Scotland Phil Verster said: “Our engineers are working hard in very challenging conditions to stabilise and strengthen the structure.
“The West Coast Mainline is a vitally important transport link for passengers and freight and we are committed to completing these works and reopening the line for customers as quickly as we can.”
UK rail minister Claire Perry said: “We are working closely with Network Rail and the train operators to make sure that the considerable damage to the viaduct is repaired as soon as possible so that the line can be reopened, and we thank them for their hard work.”
Scottish transport minister Derek Mackay added: “The record amount of rainfall that we have witnessed over recent weeks has resulted in significant damage to transport infrastructure around Scotland, including the West Coast and Highland main lines.
“I recognise the inconvenience that these works are causing to passengers. However, the safety of Scotland’s railways is of paramount concern and the severity of the damage to the viaduct meant that engineers were left with no option but to suspend all services that use it. I can assure the public that Network Rail are doing all they can to get the rail service operational again under difficult conditions.”