Police, fire and ambulance crews are at the scene of a crash involving two trains at Salisbury, Wiltshire.
The collision took place in Fisherton Tunnel, on the northeast side of Salisbury near Laverstock Junction where the line from the south coast joins the line from London.
The 5.08pm GWR Portsmouth to Bristol service struck an object and derailed, knocking out signals, Network Rail said.
It was then hit by the 5.20pm Southwestern Railway London Waterloo to Honiton train.
