Train services were suspended due to an emergency services incident in Atherton this morning.
Police and ambulance vehicles could be seen parked outside Atherton train station, while police tape has sealed off the building.
Northern said train services running between Salford Crescent and Hindley were diverted via Bolton while emergency crews attended the incident.
A replacement bus was also running between Manchester Victoria and Wigan Wallgate.
The rail operator tweeted: "Train services running through this station may be cancelled, delayed or diverted via Bolton.
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"Passengers are advised to listen for announcements and check information screens for update information where possible for your service today.
"Rail replacement road transport is running between Manchester Victoria and Wigan Wallgate in both directions."
The train line reopened at about 12.30pm.
British Transport Police have been contacted for further details.
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