Commuters faced major disruption in the rush hour after trains were unable to stop at East Croydon due to a suspect package.
Police dealt with the incident at the station and carried out a controlled explosion.
Southern, Gatwick Express and Thameslink services have all faced disrupted in the East Croydon area.
Trains were able to stop again at the station shortly before 6.30pm.
Meanwhile Motorists have faced delays of up to three hours after a lorry fire on the M25 sparked huge traffic jams stretching for 11 miles.
At around 1.30am on Friday a lorry carrying a load of metal sheeting caught fire on the M25 clockwise. 5 units and a specialised water carrier from Kent Fire and Rescue Service responded with the blaze being extinguished at around 3am.
Although the fire had been extinguished the lorry's cargo remained extremely hot and lane restrictions remained in place.
Two lanes on the clockwise carriageway between junction five, near Sevenoaks in Kent, and junction six, near Godstone in Surrey, were closed.
Traffic monitoring site Inrix said two lanes were still closed as of 11:38, despite one being briefly reopened, but "severe delays" remained.
See below for the latest updates.
