Train passengers are being warned of disruption to services across East Anglia this Bank Holiday because of large-scale bridge and track work.
Train operator One said the Cambridge and Ely line would be closed from 1000 BST on 29 April until 0300 BST 4 May.
The line between Peterborough and Cambridge will be closed from 0000 BST 28 April until 4 May.
Services between Norwich and Cambridge, Ipswich and Peterborough and King's Lynn and London will also be affected.
Buses and connecting trains will be provided for passengers affected by the work.
A spokesman for One apologised for any inconvenience caused and advised customers to check train running times with National Rail Enquiries before they travel on 08457 48 49 50.