Digby, a 20-month-old pony, began preparing for his new role by riding the metro system in Newcastle, to help him get used to the noise, people and train movements.
The pony, current owner Katy Smith and his soon-to-be-owner, Helena Hird, rode the train for 10 stops, giving Digby a chance to get used to the experience.
Helena Hird wanted a horse to help her with her visual impairment, rather than a dog, because of the animal's longer life expectancy.
Katy Smith, who runs KL Pony Therapy in North Yorkshire, said Digby has shown he's ready for the job.
"Digby is very well chilled, he's absolutely tired, he's loved the experience and so have I," she said.