Commuter who fell to her death

Detectives are investigating the death of a "bright and vivacious" City worker who fell to her death from a slam door train.

Officers are anxious to speak to passengers on the same train as Joanne Swain, 29, whose body was discovered next to tracks the morning after she caught a late-night service from London Bridge.

Her father, Richard Swain, 59, said there was no reason his daughter would have wanted to kill herself after moving into a country cottage with her partner and receiving a glittering work appraisal on the day she died.

He said: "We are completely distraught. No one knows what happened. She either fell or she was pushed and that is what we want to establish. If it was murder we want the person responsible found."

British Transport Police said it was keeping an open mind on how the death occurred. It is investigating the possibilities of foul play, a fault with one of the old-style slam doors or Miss Swain accidentally leaving the train thinking it had arrived at a station.

The body of Miss Swain, who worked for investment bank ABN Amro, was discovered near Paddock Wood station in Kent on Saturday morning. The previous evening she had caught the 10.37pm London Bridge to Canterbury West service - which calls at Paddock Wood - to her home in Staplehurst. Despite about 500 people boarding the train at various points no witnesses have come forward.

Police and family members said it was very unlikely Miss Swain, who enjoyed a successful career as an IT technician with City investment bank ABN Amro in Bishopsgate, committed suicide. Mr Swain, who also lives in Staplehurst, said: "She was a lovely, bubbly person and on a real high. She rang her partner the same day to say her work appraisal had gone well."

A spokesman for ABN Amro said: "She was an exemplary employee and a valued team worker and we are shocked by her tragic death." The company confirmed she had received a "glowing" work appraisal on the day of her death.

Her family also believe it is highly unlikely she tried to leave the train at the wrong station. Paddock Wood is two stations away from Staplehurst where she normally got off and Miss Swain fell from the train on the opposite side from the platform.

Mr Swain said his daughter had been commuting to London for 12 years and it was unlikely she would have got off at the wrong station.

The eight-car train has been impounded in Kent where it is undergoing tests by scenes of crimes officers.

Inspector David Brady, of British Transport Police, said: "We do not know what happened and we are keeping a very open mind. Any information people can give us about the last movements of Joanne would be very welcome.

"At the moment we are looking at either a misjudgment on her part or something wrong with the train's locking mechanism."

Mr Brady said there was no evidence so far to suggest foul play but it was not being ruled out.

He said there have been four incidents resulting in serious injury or death involving slam door trains in the South-East in the past year. "The potential for these types of incident is less likely with the new sliding doors," he said.

Miss Swain, described as 5ft 5ins tall, with shoulder length brown hair, was wearing a black rollneck sweater, grey trousers and a black shaggy coat when she caught the train last Friday.

Anyone with information can call British Transport Police on 0207 391 5275.