Father-of-three Nigel Jacques was fatally struck by the nine-carriage Pendolino inside Shugborough Tunnel at around 11.40am on Sunday April 24, as it approached speeds of 100mph.
The 46-year-old, from Blackburn, had cycled to the area and left his dog tied to his bike but left no suicide note or farewell message.
The inquest, held at Cannock Coroner's Court, heard how Mr Jacques had been suffering anxiety at the prospect of starting a new job after handing his notice in at Network Rail, where he had worked for 20 years.
His wife, who was present at the hearing, had advised him to take his job back, while he had spoken to an employment counsellor prior to his death and was due to see his GP the day after the incident.
Mr Jacques had been suffering with anxiety on and off for 15 years but was not known by mental heath services, said coroner's officer Andrew Heathcote.
Paul Simmonds, rail fatality investigator at the British Transport Police, said the driver of the train had 'no chance' of reacting to the man in the darkness of the tunnel.
He said: "He caught a glimpse of something brown in the train's head lamps and thought it was a deer.
"He had no chance to see him before the collision.
"He put the train into full braking and brought it to a halt just by the exit to the tunnel.
"He believed he had struck a deer and left the cab to inspect the train for signs of collision. He didn't walk back to the collision scene and remained with the train.
"A short time later he was informed he had collided with a person."
Coroner Andrew Haigh explained he had to be 'satisfied beyond reasonable doubt' Mr Jacques had killed himself before recording a verdict of 'suicide while suffering from anxiety'.
He said: "He had secured his dog to his bicycle. If you consider a possible alternative explanation of going into the tunnel to look for something I would have expected him to go in the tunnel with his dog.
"Brining all matters together I do not believe there to be any other realistic explanation for what has happened. I am sure Nigel intended to kill himself and has killed himself which was effected by his anxiety at the time."