At least 11 cows were killed after they wandered on to a railway line and were struck by a train.
A further 15 cattle were said to be missing after the southbound Great Northern rail service hit the animals near Peterborough.
Football fans travelling by rail to watch the Premier League match between Burnley and Arsenal were caught up in the delays.
Great Northern tweeted: “There are 11 cows confirmed deceased, there are a further 15 missing from the field.”
The company said the collision happened at about 10.10am on Sunday (2 October).
The incident caused the line between Peterborough and Huntingdon in Cambridgeshire to be blocked for about five hours.
— Great Northern (@GNRailUK) October 2, 2016
Paul Curry, one of the passengers on the train, tweeted: “Oh dear. My train home has hit a cow. It smells terrible.”