There will be no rail service from Huntingdon and St Neots for the next two weekends while important improvements are carried out on the line.
Replacement buses will be in place, but are expected to be busy, and will run in two formations with fast buses between Hitchin and Peterborough, stopping at St Neots and Huntingdon.
Another service will stop at all stations which will include Peterborough-Huntingdon-St Neots-Sandy-Biggleswade-Arlesey-Hitchin.
The work, staring on Saturday, February 4, is part of the East Coast Main Line £3.6 million programme to completely renew switches and crossing, also known as points, which allow trains to move from one track to another.
The project aims to increase the reliability and performance of one of Britain's busiest rail routes.
Rob McIntosh, route managing director for Network Rail, said: "There isn't ever a good time to disrupt passengers but it is essential that this piece of work is carried out when trains are not running, and I apologise for any inconvenience this may cause."
Passengers are advised to check with nationalrail.co.uk before travelling on 4/5 February, as well as on 11/12 February.