Emergency services flooded Potters Bar station today (December 31) at 1.41pm after reports of the casualty.
The person was pronounced dead at the scene.
Police are not treating the incident as suspicious and a file will be prepared for the coroner.
As a result, trains between Stevenage at Kings Cross / St Pancras may be cancelled, revised or delayed.
LNER, Thameslink and Great Northern trains have been affected.
There are a number of cancellations today, including services diverting onto the route through Hertford North.
Some services will also finish their journeys before they reach the area for example, they may not continue north of Finsbury Park, especially services from Moorgate.
There may also be some service changes affecting trains which are normally due to run via Hertford North.
To reduce congestion, stopping services may not always call at all the usual stations.
National Rail estimates that major disruption will last until 6pm, but this could last even longer.
This is likely to affect people travelling in or out of London for New Year’s Eve.
A British Transport Police spokesperson said: “Paramedics also attended, and sadly a person was pronounced dead at the scene.
“The incident is not being treated as suspicious and a file will be prepared for the coroner.”
If you feel affected by what has happened and wish to find support, you can contact the Samaritans on 116 123 via phone for a confidential chat or email jo@samaritans.org.
