Elizabeth Gaigh

In the short story The Girl in the Train, Lady Elizabeth Gaigh is one of the five daughters of the Marquis of Axminster, and the sister of Lord Roland Gaigh who wanted to marry the Grand Duchess Anastasia of Catonia. Elizabeth helped Anastasia evade Prince Osric, Anastasia's uncle who objected to the marriage. She switched coats and hats with Anastasia. Osric swallowed the ruse and followed Elizabeth to Waterloo Station. Elizabeth then got onto a train to Portmouth and asked the occupant of her compartment George Rowland to hide her, which he obliges. On the way to Portsmouth, Elizabeth gets off at an intermediate station but asks George to follow a bearded man wherever he goes and observe what he does. George is excited by the events and imagines he is on the brink on some adventure.

George later meets Elizabeth on a train again, this time coming back to London from Portsmouth. She had come to apologise to him. She explained that her instruction to follow the man with the beard was just a fiction. He looked so keen to have a real mystery of the kind he had read in books, so she had given him one. That does not upset George, who really did get an adventure, and he proposes to her.

Portrayals
In the episode The Girl in the Train of The Agatha Christie Hour, a TV film adaptation of the story, the part of Elizabeth Gaigh is played by Sarah Berger. In the book it is unclear if Elizabeth met George a second time by coincidence or she had sought him out. In the adaptation, she actually comes all the way to Portsmouth to search for him and met him at the station as he is about to depart for London.