Of course, trains do stop before detaching-attaching takes place.
They also change axles at gauge border.
I frequently have to get into a particular set of carriages on my journey home from central London, as the train divides en route.
(The subject is one of the older bad ideas from British railroad practice, along with brake vans, buffer and chain couplers, and two-axle boxcars. In the US, Congress passed the Railroad Safety Appliance Act in 1893, and by 1900, all railroad cars and engines had to have air brakes and automatic couplers. Because of this forced standardization, boxcars could become much bigger and heavier. The UK and much of the EU still don't have fully standardized automatic couplers for freight trains.)
So they used to detach cars from moving trains with passengers in them in order to keep the express running? Like, in real life and not in a cartoon? Hacker news, indeed.
And I hope so. They've been better than the links they've displaced 100% of the time.
If random Wikipedia articles routinely get a lot of upvotes, I'm not sure it's a spambot.