AN investigation was under way today after three people were killed when a train ploughed into their car on an unmanned level crossing.

Two men and a woman, all elderly, died when their car was struck by the Wick to Inverness train on the crossing at Halkirk, Caithness, at 2.10pm yesterday.

None of the 18 passengers or four staff on board the train was injured.

Last night Network Rail staff inspected the crossing, which has no barriers and uses only a warning light system.

"At this stage, there is nothing to suggest that the crossing was not functioning correctly at the time of the collision," said a spokesman.

In 2002, the same crossing was the scene of a serious accident when a pregnant woman, Sarah Jappy, was badly injured and put in a coma after her car was hit by a train.

Ms Jappy is suing Network Rail for £500,000, and a case hearing is due later this year.

Her solicitor, Cameron Fyfe of Ross Harper solicitors, said: "This tragic accident appears to be similar to that involving Sarah, and in her case we are arguing that if there had been a barrier the accident would never have happened.

"It may be that the same questions will now be raised all over again."

A joint investigation between Northern Constabulary and British Transport Police has been launched to determine the circumstances that led to yesterday's accident.

The Rail Accident Investigation Branch will hold its own inquiry.