Rail passengers planning on travelling from Corby, Kettering or Wellingborough this weekend will face significantly longer journey times.
Buses will replace all trains between Corby, Wellingborough and Bedford on May 11 and 12 for major work as part of the Midland Main Line upgrade.
Over the weekend Network Rail engineers will install four new sets of points at Sharnbrook Junction on the line between Kettering and Bedford.
As a result no trains will operate between Wellingborough and Bedford with replacement buses running between the two stations.
Anyone travelling south from Kettering will have to get a train to Corby before getting a replacement bus to Bedford with the journey in reverse for anyone travelling to Kettering from the south.
Trains will run between Bedford and London St Pancras but will not call at Luton or Luton Aiport Parkway.
Network Rail say the work is vital in the construction of a new line between Bedford and Kettering, which will enable six trains per hour to London St Pancras by the end of 2020, up from the current five per hour.
Rob McIntosh, route managing director for Network Rail, said: “I would urge all passengers planning to travel between Bedford and Corby this weekend to plan ahead and check before they travel as work takes place as part of the Midland Main Line Upgrade.
“This work is really important and is the latest stage of work to construct a fourth rail line between Bedford and Kettering which will provide the capacity for more services to run.
“This will enable us to continue to railway which meets the needs of the passengers, communities and economies we serve.
“There’s never a good time to work on the railway, we do so at the weekend as it is a time when fewer people travel, but we do understand it can still cause disruption and we do apologise for this.”
Jake Kelly, managing director for East Midlands Trains, said: “As the Midland Main Line Upgrade work continues, we are advising any passengers travelling to Bedford and Corby on May 11 and 12 to check before they travel as their journeys will be disrupted.
“We apologise for any inconvenience caused by the disruption during this time.”
To check your journey visit https://www.nationalrail.co.uk/