According to the latest update from Network Rail, 8 passengers and 2 crew members were on board the train that derailed near Bargoed this morning.
There were 3 reported minor injuries, which were treated at the scene.
The emergency services and Network Rail are on site dealing with the incident.
Trains on the Rhymney Valley line are starting and terminating at Bargoed, with a bus service running between Bargoed and Rhymney.
More top news
Not a promising start to the week with a Met Office yellow warning of heavy and persistent rain.
There'll be bracing winds and heavy showers this afternoon and expect a wet and windy start on Monday morning.
Carl Edwards and guests look back at the week's events in the latest edition of Newsweek Wales.