A trespasser was found on train tracks at Bickley last night.
Delays to services between Bromley South, Orpington, and Swanley were reported at around around 9pm.
Both First Capital Connect and Southeastern were affected and notified the public of disruption on Twitter using the hashtag #Bickley.
However the trespasser was said to have been caught soon after.
One user on the social media site tweeted: "Male located on the tracks by I99, local units and British Transport Police guided in and male detained without incident."
National Rail announced soon after the individual had been removed and all lines were open, though added there was a risk of 15-minute delays to journeys until midnight.
- Runner helping exhausted athlete over finishing line 'is what London Marathon is all about'
- North Korea accused of using south London-based insurers to fund nuclear weapons programme
- Water stations, urinal bays and MP runners: The 2017 London Marathon in numbers
- Police arrest man on suspicion of funding terrorism
- Record number of runners to take on today's London Marathon