A major project to upgrade the swing bridge at Sutton Bridge should finish this week.
The last of four sets of lifting jacks on the Cross Keys Bridge were installed on Monday evening.
The busy A17 route between Lincolnshire and Norfolk was closed overnight to allow the contractors to finish the work.
“The work has been carried out using single night closures to minimise disruption on the highway network,” said Karen Cassar, assistant director for highways at the county council.
“The hydraulic lifting jacks are fundamental to the operation of the iconic, working swing bridge. Over the course of time they naturally wear out and require maintenance so that they keep operating. The four jacks in situ were identified as faulty and in need of urgent attention.
“Expert teams have been going through the jack-by-jack process of carrying out four separate maintenance schemes, each of which has involved a night time closure of the bridge.
“The jacks are fundamental to the operation of the iconic, working swing bridge,” she added.
The bridge was first built in 1897 and remains the only crossing point for both traffic and pedestrians over the River Nene north of Wisbech.
There was a railway line which closed in 1965 and it remains a key structure.