Rail services have been brought to a standstill between Uckfield and Crowborough while engineers investigate a potential track fault.
All train operations on the line have been suspended as a safety measure while the investigation continues.
The disruption was triggered when rail officials reported a possible problem with the infrastructure in the vicinity of the affected area.
Network Rail engineers were dispatched to conduct a thorough examination of the track.
As a precautionary measure, no trains have been permitted to operate through the section while checks are underway.
Passengers travelling between the two stations face significant delays and should anticipate their journeys taking at least an additional 30 minutes.
The suspension is expected to remain in place until approximately midday, with alterations to scheduled services anticipated throughout the morning.
Replacement bus services have been mobilised to assist travellers in completing their trips.
The road transport is operating between Crowborough, Buxted and Uckfield, providing an alternative route for those affected by the line closure.
Rail authorities have indicated that track inspections typically encompass assessments of whether rails maintain proper support, verification that the track bed remains in satisfactory condition, and checks that fixings and metalwork continue to function as intended.
Services will not resume until engineers have formally confirmed the line is safe for operation.
Travellers are being directed to consult journey planning resources or liaise with station personnel for current information regarding service availability and alternative travel arrangements.
