'Massive flashes' as electrical fault at Dorchester delays South West Trains
An electrical fault caused sparks to fly, blocked rail lines and disrupted South West Trains services.
The rail firm said the issues were due to electrical supply problems at Dorchester South station in Dorset.
Some onlookers, including David Crane, took to Twitter to describe "very bright flashes and lots of emergency services".
No-one was injured but police, the fire service and ambulance crews were called.
BBC South digital editor Dan Kerins, who was on a train when the problems began at about 18:15 GMT, said: "There was a small spark on the track and, as the train ran over it, it was like a flare had gone off.
"Massive flashes of light lit up the whole train. One of the carriages was filled with smoke for a time."
A South West Trains spokesman said: "Passengers were taken off the 18:03 Weymouth to Waterloo service at Dorchester South station after reports of electrical arcing underneath the train.
"Emergency services were called as a precaution, but were not required. There was no fire, although the incident did result in flashes, smoke and a bang, as well as cosmetic damage to the train."
The company provided a replacement coach service for affected passengers and apologised for the disruption.