One traveller due to leave London at 7pm for a journey that normally takes 28 minutes did not arrive at his Hertfordshire home until 1.45am.
"It's absolutely outrageous that something like this can cause such a long hold-up," he said.
Network Rail said today that the West Coast main line had to be shut around 7.30pm yesterday after a person was hit by a train at Kings Langley in Hertfordshire.
The line reopened at 8.22pm but passengers using the services operated by the Southern, London Midland and Virgin train companies endured delays.
An NR spokeswoman said: "We always try to get lines open as quickly as possible on these occasions. But there can be subsequent hold-ups if lines are blocked."