While this is not one of the best of Brian Clemens's "Thriller" anthology it is still a very capable effort and is worth seeing if you have the opportunity.
The story opens with an attempt to kill an East European defector. It then switches to a young American woman, Helen Marlow. She is booked onto a luxury train journey to aid her recovery from a nervous breakdown following the death of her fiancee. An Australian traveller, Bob, befriends her but it is tough going as she is still very depressed. Her distress becomes much worse when she seems to see a dead passenger. Bob and others assume she is hallucinating but she is quite convinced. However there are people on the train who are not what they seem, and who have murder on their mind...
This is one of the stories with an espionage theme. It bears similarity with "Good Salary - Prospects - Free Coffin" that aired only four months later. Both episodes centre around elaborate impersonation schemes. These plans are rather stretching credibility but are necessary to a solid story. A key figure in all this, and "star of the show" is the brilliant character of Hilary Vance. Vance is an elderly diplomat, cultured and witheringly sarcastic, demolishing the hapless train staff with his wittily-delivered complaints. Vance is extremely entertaining and very funny, but it is a very natural humour that doesn't detract from a serious story. The character of Helen Marlow is also well-handled. Her depression is quite authentically projected.
There is some good acting, most notably from Charles Grey as Vance and Judy Geeson as Helen. The climax is quite sharp, with an impressive final line from Helen. It is interesting to see Duncan Preston as part of a newly-married couple who turn out to have matters other than romance on their minds. Preston later became a frequent face on TV, usually in comic roles such as accompanying Victoria Wood. Jim Smilie very much looks the part as the smoothie Bob. His charm maybe comes a little too easy and reflects the more traditional image of the sexes that permeates so many "Thriller" episodes. All the same his role is well-done and contributes to a superior piece of television.