Mellin Kinloch-Jones

 was a member of the Business class on a train-city on a devastated planet. His mate was Emiliege. They had a rebellious daughter.

Mellin and Emiliege met the Fifth Doctor when he appeared in their compartment. He pretended to be an inspector investigating the recent suicides. Mellin and Emiliege explained the train-city to him.

In reality, Mellin and the entire train-city were part of an illusion that Maya had created for the Doctor and Nyssa. (PROSE: Confabula)