Emergency service workers transport an injured passenger on a stretcher to an ambulance after a train accident in Soweto May 19, 2011. [Photo/Agencies]

JOHANNESBURG - A train crash injured more than 640 passengers on Thursday night in South Africa's Soweto township outside Johannesburg, local media reported, citing emergency services.

South African news agency SAPA said two of the injured were in a critical condition. It said a train had apparently collided with a stationary one in Soweto, the country's biggest black township.

Commuter train accidents are a regular occurrence in South Africa. In 2009 almost 300 people were injured in two separate train accidents that occurred hours apart.

In 2006, 27 people were killed when a truck carrying farm workers collided with a commuter train at a railway crossing.