1)Well, the whole "Orient Express in space" bit goes back to a line at the end of "The Big Bang", where there is mention made of an Egyptian goddess loose on the train. Love a good space-train story, going back at least as far as Galaxy Express 999.
2)So, Clara's back for "one last trip"? I thought we might see him have an adventure by himself for a change.
3)"Can I talk about the planets now?" Funny watching him evade conversation about emotions.
5)"Old ladies die all the time. It's practically their job description."
6)The scene with the Doctor talking to himself was amusing also.
7)Coleman certainly looks "interesting" in that dress.
8)"A mystery shopper." Do those actually exist?
9)Hmm, Perkins seems to be more than just a simple engineer. He even seems to know a little abotu how the TARDIS works.
10)I wonder if the mystery of who GUS is is tied into who "Missy" is?
11)"I'm the Doctor and I'll be your victim this evening. Are you my mummy?" Calling all the way back to "The Empty Child". Cripes, the Eccleston months seems ages ago, don't they?
12)The bit at the end with Clara seemd like an awkward bit of writing to me. So she essentially lies to both Danny and the Doctor to cover up the fact that she can't bring herslef to stop traveling with the Doctor. With the talk of addiction at the end, I guess they're running with the idea that Clara is addicted to her adventures.
Overall: Not bad. Could've used a bit of editing in parts, but I enjoyed it. Capaldi's Doctor continues to be an interesting change for me.
This post at Pappy's Golden Age Comics Blogzine has the cover and story "The Train that Traveled Through Space" from Captain Marvel Jr. #114, and an ad that may have inspired them.
According to Wikipedia, here, Galaxy Express 999 was inspired by the novel Night on the Galactic Railroad by Kenji Miyazawa, which was written between the wars. Wikipedia's page on the novel has a detailed summary.
Thanks for the info, gents!
Sometimes they're called "mystery shoppers" in the U.S. (or "secret shoppers"):
ACG's Forbidden Worlds #87 has train-in-space imagery on its cover, but in the story (drawn by John Buscema) it instead passes through alternative dimensions.
Tales of the Unexpected #53 had a story called "Express Train to the Stars", but it wasn't cover-featured.
This post displaced The 75 Greatest Marvel Comics from the home page.