British Transport Police later confirmed the incident involved the welfare of a man.
All lines were blocked as a result, meaning trains running through Preston were either cancelled or severely delayed.
“Officers are on scene working to bring the incident to a safe conclusion,” a spokesman for BTP said.
At 4pm, National Rail confirmed all lines had reopened after the man had been returned to a position of safety.
Passengers were warned services could still be cancelled or delayed by 60 minutes, with “major disruption” expected to last until approximately 7.30pm.
Road transport was requested by National Rail to help customers affected by the disruption.
The routes affected by the incident were:
Avanti West Coast
- Edinburgh / Glasgow Central / Blackpool North and London Euston
- Blackpool North / Windermere / Barrow-in-Furness and Manchester Airport
- Blackburn and Preston
- Blackpool North and Liverpool Lime Street / Hazel Grove / York
- Blackpool South / Colne / Liverpool Lime Street / Ormskirk and Preston
- TransPennine Express
- Glasgow Central / Edinburgh and Manchester Airport
- Glasgow Central and Liverpool Lime Street