Emergency services are currently dealing with an incident on a platform at Clapham Junction.
Services in and out of the station are currently delayed as officers deal with the issue.
Officers were called at 12.28pm to reports that a woman had fallen between the platform and the train.
National Rail says that services are likely to be disrupted until at least 2pm.
The woman has been taken to hospital but her injuries are not believed to be serious.
The incident is not thought to be suspicious at this time.