How long can a train be in Canada?

Wow, ever wondered just how ridiculously long a train can get in Canada? I have, especially after seeing one stretching forever while driving alongside the tracks – felt like it went on for miles! Anyway, turns out it's not quite as simple as just saying a number.

It depends on a few things, mostly about the air brakes. See, for regular freight trains (not the ones with containers or just carrying one thing like coal or oil), there’s like a starting length. Then, for every extra set of air brakes they add – these "air sources" – they can tack on another 1500 feet! Makes sense, right? You need more braking power the longer the train is. I think they can have up to five of these extra air sources.

And the absolute longest a train can be in Canada? A whopping 12,000 feet! Can you imagine?! That's like, uh… well, it's over two miles long! Crazy, isn't it? I remember reading somewhere that some of the longest trains in the world operate in Australia, though... maybe I'm mixing things up. But still, 12,000 feet is seriously long.