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.
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Mainly dry at first today with patches of cloud and possibly showers later on. Highs of 16°C.
South and east Wales will stay dry tonight, there will be clear spells and very little wind but mist developing in the valleys.
Black History Month celebrations are continuing with a showcase of youth talent at the Wales Millennium Centre.