The Virgin East Coast driver sheltered next to his cab just three seconds before the high-speed train passed.
The 3 August incident happened 12 miles (19.7km) north of York station.
A report said it was the result of a lack of "clear understanding" between the driver and a trainee signaller over whether a line blockage was in place.
Live updates and more from across North Yorkshire
The Rail Accident Investigation Branch report said the driver was attempting to carry out tests on the 07.55 BST Inverness to London King's Cross train when it experienced a loss of power at Kyle Beck, near Tollerton.
It said the driver contacted the signaller - a trainee working under the guidance of an experienced colleague - to request trains on the adjacent lines be stopped in order to carry out the checks.
After communicating the request, the signaller said he would call the driver back to confirm the line blockage.
But, the report found, the driver stepped down from his cab before receiving the confirmation.
A CCTV image taken from the front of the passing train showed the driver sheltering next to his vehicle. The driver was unhurt.
"It is possible the driver may not have heard what the trainee signaller said or that he had misunderstood what he was being told," the report said.
"The driver and the trainee signaller did not reach a clear understanding about stopping trains on the adjacent lines and the driver subsequently alighted from the driving cab of his train, incorrectly believing it was safe to do so."

The 27-year-old Scot pulled out of a planned performance at the O2 Arena in London on Thursday, as well as Friday's gig at the Motorpoint Arena in Cardiff.
Nutini - whose third album Caustic Love topped the charts earlier this year - postponed two concerts in Glasgow this week on medical advice.
Fans with tickets should keep them and look out for the rescheduled dates.
A statement announcing the latest postponements said: "Regrettably Paolo Nutini is suffering with severe tonsillitis and is not well enough to perform."
It also offered an apology for the "inconvenience and disappointment" caused.

Police said detectives were investigating the blaze which started shortly before 04:50 GMT on Coniston Road.
The force added the fire is being treated as unexplained and a joint investigation with the fire service has been launched.
Lancashire Fire and Rescue Service said it sent five fire engines to the scene to tackle the blaze.

They have until 20:00 local time (19:00 GMT) on Tuesday to leave the southern part of the sprawling camp.
Anyone remaining will be forcibly removed to allow for the makeshift structures there to be  razed.
The area has become a cultural hub for many of the migrants. It has shops, a school and religious structures.
The authorities said up to 1,000 people could be affected but volunteers on the ground estimated that at least twice that number lived in the area.
Thousands of migrants from the Middle East and Africa have congregated around Calais in the hope of crossing to the UK.
A train driver narrowly avoided being hit by a second train travelling at 105mph (169km/h) when he was investigating a power failure.
[NEXT_CONCEPT]
Chart-topping singer Paolo Nutini has postponed a two more UK arena shows due to "severe tonsillitis".
[NEXT_CONCEPT]
A person has died in a house fire in Lancaster.
[NEXT_CONCEPT]
Hundreds of migrants living in part of a camp in the French port of Calais known as the Jungle have been ordered to leave or face eviction.