Rail services on the Dundee to Perth line were briefly suspended on Tuesday after a car collided with a bridge.
Network Rail Scotland engineers are understood to have inspected the bridge before deciding it was safe for services to resume.
A Network Rail spokesperson said: “Our engineers were quickly on-site to inspect the structure and reopen the line for customers.
“All of our structures are clearly marked with the height for vehicles and motorists have no excuse for striking bridges.”
ScotRail had announced all lines were blocked as a result of the collision, before saying the line had been allowed to reopen a short time later.
A number of services were disrupted as a result of the incident on Tuesday morning, including trains travelling between Glasgow and Dundee.
It has not been confirmed which bridge was affected by the incident.
ScotRail said on social media: “The bridge has been reviewed and the line is now safe to reopen.
“A speed restriction of 5mph will remain in place as a precaution.”