Network Rail is warning passengers that buses will replace trains between Bedford/Luton and London St Pancras and between Leicester and Peterborough this weekend (Saturday 10 and Sunday 11 May).
During the series of weekend closures on the Midland Main Line, Network Rail has been able to complete essential maintenance work alongside the major project.
On weekends until the beginning of June, train services on the southern part of the Midland Main Line will be subject to major disruption.