Train services via Dumbarton were restricted on Friday after a van struck a railway bridge.
Operator Scotrail announced that services between Dumbarton Central and Bowling would be slowed on Friday morning.
It came as a team of the firm’s engineers raced to carry out checks on the bridge at Castlegreen Street in Dumbarton East, after the structure was hit by a van.
Onlookers say the vehicle, from charity The Beacon Trust, hit the structure during the incident on Friday morning.
Scotrail told commuters on Twitter that their engineers were expected on site by noon.

They announced by 12.30pm that the bridge had been declared safe and normal service would resume.
A spokesman for Police Scotland confirmed the incident, saying: “Around 10.45pm on Friday, 16 July, officers were called to Castlegreen Street in Dumbarton after a van collided with a railway bridge.
“There were no reports of serious injuries and the obstruction was cleared by around 12.30pm.”
A spokesman for Scotrail added: “There was an initial impact on some services but the issue has been resolved and services are running as normal.”