Charleigh Disbery, 15, and Turkish boyfriend Mert Karaoglan, 18, died after they were hit by an empty First Capital Connect train.
In a statement, the driver said he ‘did everything he could to slow the train but to no avail’.
Shortly before, Mert texted a friend near Elstree and Borehamwood station to say they ‘would never be together in this life’.
He sent a photo of them smiling on a bridge over the line.
Charleigh, who had a history of depression, and keen photographer Mert met at the Hertswood Academy, Borehamwood, where they studied.
Hertforshire deputy coroner Graham Danbury said the pair were ‘in a close relationship’ for about a month before their deaths on June 17 last year.
Recording verdicts of suicide, the coroner added: ‘Because of Mert’s background it seems like a relationship between him and Charleigh would not have been approved by his family.
‘Such was the intensity of their feelings for each other they ignored the effect their acts would have on others – family, friends and the train driver.’