Snowpiercer, an at times very funny and at times very bleak post-apocalypse SF movie set on the last train on Earth, which trades on Chris Evans being Captain America to affect our expectations of his character and features Tilda Swinton and John Hurt together in the second genre movie of the year, is definitely a one-shot.
Based on a graphic novel rather than a series, with a plot and locations purposely limited by the premise, it could be expanded by sequels and prequels but should really remain self-contained. The train is a classic enclosed location, like a Base Under Siege or anywhere else you cannot leave. I rarely use maps and precise NPC cast lists, but they work well for adventures like this.
(To put it in a series, it could easily be a planet of the week for someone like the Doctor or Captain Kirk to visit and save, which would overshadow the heroism of the locals.)
It also features one of the oddest threats I have seen on screen. You’ll know it when you see it.