Richard Straw died instantly but amazingly his daughter Scarlett was thrown clear of the train.
Train driver David Dobson said he saw Mr Straw run straight in front of his Leeds-bound express.
"He looked straight at me and seemed to speed up. I could see he was carrying a girl," he said in a statement," he told an inquest.
"She was being carried on his left hip and had her arms around his neck, and her head on his left shoulder. It was apparent he intended to jump straight in front of the train."
It later emerged that Mr Straw was filled with hatred for Scarlett's mum, Samantha Roberts, 25, after splitting up with her the day before because he suspected her of having an affair, an inquest in Doncaster heard.
Police found evidence he may have intended his daughter to die with him. Samantha had moved out of the home she shared with Mr Straw for four years and gone to her mother's.
After the tragedy police found graffiti on the walls of the house reading: "You always wanted me dead" and "mummy I love you, goodbye".
Samantha told the hearing her ex-partner was 'a really nice and a loving dad' and she never thought he would hurt Scarlett. But he could change and become 'awkward and nasty'.
The day before his death in July last year Mr Straw, of Bentley, Doncaster, learned Samantha had been seeing his friend, Lee Bacon - whose house he was then suspected of setting on fire.
A letter to Samantha found in his car near the railway line at Adwick-le-Street said: "I'm having Scarlett, she's coming with me, far, far away from you. Can't wait for the train to come."
Detective Constable Ian Grice told the inquest there was 'extensive graffiti' at the house expressing hatred for Samantha.
"It was obviously the work of someone not thinking straight. It was quite disturbing," he said.
On July 11 last year, Samantha had been due to take Scarlett to buy her first school uniform but Mr Straw turned up pleading to take the child to the park.
"He promised she'd be back for 12 o'clock," she said. "He was calmer than he had been. He told Scarlett to say goodbye to mummy."
When they didn't return for midday Samantha began to worry, and was at his house when police arrived.
"I read some of the messages on the staircase just as the police turned up," she said.
"It was all hatred towards me." The warehouse worker had also been arrested around that time when the home of his suspected 28-year-old love rival Lee Bacon was set on fire.
But it was only on the day before the tragedy that Samantha believed he had become certain she was seeing Mr Bacon.
Samantha told the hearing: "I think he found out properly. I had started seeing someone, but it was not serious."
Samantha said her daughter was now well enough to go to nursery school. The Coroner recorded a verdict of suicide.