Work to strengthen the railway bridge over Ermine Street in Huntingdon will create road diversions as improvements start this weekend.
The bridge which carries the East Coast Main Line through Hutingdon will undergo strengthening work, minor repairs and receive a special protective coating.
The work has been split into two separate phases to minimise disruption to trains as well as drivers.
First stage of work will begin this weekend, meaning signposted diversions will be in place for traffic between 9pm on Saturday, November 8 and 5am on Monday, November 8.
The same road closures will then take place for the next five weekends finishing on Monday, December 13.
Mark Tarry, route managing director at Network Rail said: "The work is being carried out in two phases to keep disruption levels as low as possible for the people of Huntingdon and I'd like to thank them for their patience while the work takes places."
The second phase of work will not being until February next year, with the work being split over two periods to further reduce disruption.
Ermine Street will remain open to pedestrians and cyclists throughout the upgrade work.
Members of the Network Rail project team held a drop-in session at Huntingdon library on Wednesday, November 4 to answers residents' questions and explain the plans that are in place to keep disruption to a minimum.