LONDON, Oct 31 (Reuters) - Two trains collided on Sunday in a railway tunnel in the southwestern English city of Salisbury, injuring a number of people, police said. "A number of people have been injured, but thankfully no one has died," British transport police said. The incident occurred in a tunnel near Salisbury station and there were reports that a train had derailed. Fire trucks and ambulances were at the scene, Wiltshire police said. The BBC said one of the train drivers was believed to have been trapped in the cab of the train. Train operator Great Western Railways said the incident involved a train travelling between Portsmouth and Bristol and another train which was travelling from London"s Waterloo Station to Honiton.