East Midlands Railway will run a significantly reduced timetable to and from London on Sunday and Bank Holiday Monday.
Services are expected to start from around 8am and finish before 7pm.
There will be one train an hour between Nottingham and London St Pancras, Sheffield and London St Pancras, and Corby and London St Pancras.
Passengers are being warned trains will be extremely busy, with queuing systems in place at London St Pancras and Sheffield.
EMR says people may not be able to board their intended service or get a seat.
The disruption is expected to be worsened by planned East Coast Main Line engineering works, with no LNER trains between London King’s Cross and Peterborough on Sunday.

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