Mick Ward, from Harrogate, was found guilty of common assault last year following allegations made against him relating to an incident at Knaresborough railway station.
The 42-year-old denied the charge that he had taken a young passenger by the throat and pushed him against a wall last April.
But the charges against him have now been dropped after a hearing at York Crown Court where prosecutors decided not to oppose his appeal.
Mr Ward’s solicitors said the Crown Prosecution Service and British Transport Police failed to reveal to the original magistrates’ court hearing in December that the passenger was issued with a youth reprimand order for unruly behaviour on the day of the alleged assault.
The driver, who has been suspended from work since July, claimed he was verbally abused by the passenger and used reasonable force to move him away from the train for his own safety.
Speaking after the hearing on April 12, where he was joined by more than 30 colleagues and members of union ASLEF, he said: “This has put a great deal of strain on me and my family, both emotionally and financially due to my suspension, but I was determined to set the record straight.
“I am disgusted that the British Transport Police stood by and let my reputation be dragged through the mud.”
Craig Hunn, of Thompsons Solicitors, said: “The unprecedented level of support Mick has been shown by his co-workers shows just how badly the British Transport Police dealt with this case.”
Adrienne Gower of CPS Yorkshire and Humberside said prosecutors had not been made aware of the reprimand given by police to the young passenger, so could not pass it onto the defence.
She said: “The failure to inform the defence put the prosecution team in breach of its duties of disclosure, and after careful consideration the CPS decided not to oppose the appeal against conviction.”
A British Transport Police spokesman said: “As a matter of urgency we will be reviewing the file which was compiled for the Crown Prosecution Service in relation to this case.”