I'd put bets on yours being the Jubilee line then, that loud whine is etched into my soul. One thing this couldn't capture for the Central line is the sheer volume of it.

I couldn't tell them apart

And yet I could tell them apart with pretty good confidence. Why?

I got 5 out of 9 and have never used the london underground. The repeat multiple choice, a good memory, and me reading that the jubilee line makes a screech in the comments pushed me over that 50% mark!

I got 8/9. Been away 2 years. The ones I rarely used or which don't have obvious "tells" that are hardest. For me, Jubilee is the most obvious - very distinctive sound.

I got five and I have not lived there for over 20 years.

Got 3/9 and live in London. Really only a single one of which I both had confidence in and got right.

Most people on the tube have headphones in anyway tbh.

> Don’t they use the same rolling stock and cover very similar stations?

Same stock, yes.

But stations different. Circle is Zone 1 and so almost entierely covered except for very short sections. But District has a lot of open track sections.

The Bakerloo sounds are indeed pretty distinctive (I lived near Kilburn Park for a while and knew it well!). But I think the easiest of all is the Jubilee line. Those melodic sounds from the traction motors that rapidly change pitch when accelerating/decelerating are so distinctive and unique.

Jubilee I found pretty easy too

You can…but, won’t the frequency will be stable across the UK grid and these are all in London. Secondly, pretty sure they all use DC motors, so no hum

I got 6/9 and I've never been there.

Doesn't NYC mostly (mostly) use the same trains across the network? on the tube, each line was (historically) operated by a different train company, so most lines have a (somewhat) different profile but dedicated rolling stock to each line, along with different aged stock dependent on the procurement cycle or even age of the line itself.

Boston T would be a better one as each of the colour lines are significantly different from each other, especially concerning green line trolleys. Even having not lived there for a number of decades I could probably still pick out at least red and green line. I might struggle to pick apart orange and blue line from each other as they are pretty similar trains, but I never spent significant time on that line... (My dad was a complete train nut and spent much of his spare time audio recording train rides around the world and when we lived in Boston, the local subway got the bulk of his attention. Here in the UK his hobby even got picked up by various TV companies and he got brought onto various talk shows to demonstrate his "Blind trainspotting" prowess by identifying various trains from their sound. All a ruse of course but it was a fun gimmick for a couple of years.)

Technically, not an underground line.

are you aware that the Metro in Paris has trains with rubber wheels?