Thousands of commuters at Euston station have been left stranded after train services were cancelled due to a fatality at Hemel Hempstead.
Chaotic scenes greeted passengers as they were told by National Rail their journeys between Milton Keynes Central and Euston could be delayed by up to 60 minutes.
A spokesman from British Transport Police said: "We were called to Hemel Hempstead station shortly after 1pm to reports of a person hit by a train.
"Officers attended with colleagues from Hertfordshire Police and the East of England Ambulance Service but the person was declared dead at the scene."
National Rail said replacement bus services were being offered to commuters, while some Virgin passengers were offered alternative routes.
London Midland said Hemel Hempstead station has reopened.
But passengers took to Twitter to vent their frustration over the delays.
Robert Oliver wrote: "Sat in the first-class lounge at Euston which is beyond full, how will you prioritise passengers when the trains do start running?"