Network Rail engineers worked around the clock for four days at locations between Craigendoran and Crianlarich from November 9 until the early hours of Wednesday morning.

At Craigendoran, work took place to renew track and replace switches and crossings – movable sections of rail that allow trains to swap between lines.

Further track renewal work took place between Helensburgh Upper and Glen Falloch with over a mile of railway being replaced across these locations.

A bridge over the railway at Garelochhead has also been refurbished, with engineers blasting off old paint, carrying out steelwork repairs and repainting the structure.

Specialist geotechnical engineers also undertook earthworks inspections between Helensburgh and Crianlarich during the four-day closure of the line.

While the works took place, replacement buses kept passengers on the move.

Ross Moran, Network Rail Scotland route director, said: “This vital work will help improve performance and reliability for our customers. Our engineers have worked around-the-clock to complete these projects quickly, with as little disruption as possible, and we thank our passengers and freight customers for their understanding while this crucial investment took place.”