Southern, Thameslink and Gatwick Express services are all experiencing delays after a person was hit by a train.
The person was hit between East Croydon and Clapham Junction. Southern are warning passengers of delays and diversions.
Police are appealing for witnesses after a man was attacked on the platform at Clapham Junction station. The victim was assaulted between 11.30pm and 11.50pm on Saturday, 23 November.
PC Neil Allison, from British Transport Police said:
"The victim was standing on the platform when two men he did not know approached him. One of the men proceeded to hit him in the face, and another hit him with a belt. He did not receive any lasting injuries but was left very shaken up by the encounter."
After the assault, the suspect got off the bus and headed towards Lambeth Walk. The victim, who has not been named, was taken to St Thomas' Hospital with a head injury and released later that day.
The suspect is described as a light-skinned black man of slim build. He is approximately 20-years-old and wearing a black T-shirt with a patterned pocket on the chest, dark trousers and a baseball cap worn back to front.
A woman has been knocked unconscious after a violent attack on a bus in Lambeth. The 22-year-old was heading towards Clapham Junction when a man got on, and headed towards the back of the bus where the victim was sitting.
A can of drink was poured over the victim who was then kicked in the stomach before falling unconscious. Police are trying to find a man seen on CCTV around the time of the attack.
Firefighters based at the fire station nearby had heard shouting in the street and went out to investigate, where they were confronted and threatened by the man.
The 26-year-old suspect remained hostile and struck the window of one of the first police cars when they arrived.
Eyewitness Jenilee Graham said she was unaware there was a situation developing until a woman stopped her and told her to get away.
The 23-year-old City worker, from south London, said:
A man has been arrested on suspicion of murder after police discovered the body of a second man stabbed to death at a home.
Police carrying out a welfare check broke into the home in south London shortly before 9pm yesterday evening and found the body of a 21-year-old man who had been stabbed in his heart and lung.
They also discovered a 30-year-old man who was suffering from neck wounds at the home in Lavender Sweep, Clapham Junction.
He was taken to hospital, where he remains in a stable condition, and arrested on suspicion of murder.
South West trains advises customers to contact them for complaints and to request refunds.