Rail passengers travelling from Corby, Kettering and Wellingborough will be faced with a replacement bus service this weekend.
Engineering work is taking place on the line between Leicester and Bedford meaning no trains can run between the two stations.
Tomorrow (Saturday) southbound trains from Sheffield, Derby and Nottingham will terminate at Corby and will not call at Market Harborough.
An East Midlands Railway spokesman said: "An express rail replacement coach will run between Corby and Bedford, where you can then connect with a train from Bedford to Luton, Luton Airport Parkway and London St Pancras International.
"If you are travelling to Market Harborough, Kettering or Wellingborough you should, there will also be rail replacement services, please change at Leicester to connect with these."
Northbound trains tomorrow from London will terminate at Bedford where a coach will take passengers to Corby, via Wellingborough and Kettering, where trains will run to the north.
The same bus replacement service will run on Sunday (September 1) although the line between Bedford and Luton will be closed until 11am, with buses being extended to run to Luton.