A lorry driver crashed into the underside of a railway bridge after misjudging the height restrictions.
Police were called to the scene at 11.23am on Friday after the Spar lorry became wedged under the bridge in London Road, Hemel Hempstead.
The road was closed while the lorry was recovered and reopened just before 2.30pm.
Network Rail say staff inspected the bridge but found “no damage” after slowing trains for 20 minutes as a precaution.
A spokesman for Network Rail said: “Bridge strikes can cause delays and disruption to thousands of passengers – and are completely avoidable.
“All drivers are urged to know the height of their vehicles and to never assume their vehicle will fit under the bridge.”
One fire engine from Watford attended the scene along with British Transport Police, and members of the Hertfordshire’s Highways Department.