Lightning causes rail delays between Peterborough and London
Lightning strikes on rail signals have caused delays between London Kings Cross, Peterborough and Cambridge.
Lightning hit signals at Hertford North at about 1300 BST causing delays of 90 minutes on First Capital Connect services from London.
The delays on Capital Connect services have cleared, but passengers on East Coast trains between London Kings Cross and Peterborough face some disruption.
East Coast said there would be delays and cancellations during the evening.
A spokesman advised passengers to check the East Coast website before travelling.
Flooding at Kennett has caused delays for train passengers using National Express East Anglia between Bury St Edmunds and Cambridge, and between Bury St Edmunds and Ely.
A replacement bus service was being provided.