Rail journeys from Higham through to Northfleet could be extended by nearly an hour when 15 days of work is carried out at Gravesend railway station.
Southeastern has announced that engineering works will start on December 22 and run until January 5.
All lines will be closed and no trains will run between Northfleet and Higham.
Rathmore Road in Gravesend will also be closed whilst £19 million of work is carried out at Gravesend train station.
The station’s platform will be extended to allow for longer 12-car trains, a new footbridge will be built, and lifts installed to provide access to all platforms.
A third platform will also be added.
Part of the works will include a 15-day closure over Christmas and New Year, from December 22 to January 6.
This is needed to complete the track layout changes and station construction work. An additional platform will also be fitted. Buses will run between Greenhithe and Gravesend through to Strood.
Customer relations manager for Southeastern Alison Nolan said: “The work at Gravesend is critical for us to be able to increase capacity and run longer trains on the network, but we know the work to make this happen will result in some inconvenience for our passengers.
“We’ve spent a great deal of time working together with Network Rail, Transport for London and local bus operators to develop a range of alternative travel arrangements for customers during this time.
"We’ve written directly to our customers to give advanced notice of these plans and to enable people to plan their travel this Christmas,” she said.
CG version of how the station will look once completed
Network Rail’s route managing director for Kent Fiona Taylor said: “Gravesend station will be vastly improved and the reconstructed platforms will mean longer trains can be accommodated, providing more seats for passengers.
“It is a complicated project which requires the station to be closed for 15 days to carry out the work to the track and station.
"We recognise that this will cause some disruption to passengers’ and we have timed the work to take place over what is traditionally a less busy time on the railway.
"We are working closely with Southeastern to minimise the impact as much as possible and I am confident the long-term benefits to passengers will outweigh the short-term disruption.”