In the Shanghai's metro, I was really impressed by the ads using persistence of vision in the tunnels :) https://www.youtube.com/watch?v=WsdF834vXkQ&t=0m32s The quality is better in person than in this video, because the camera's shutter speed creates artifacts.

> There was a mass of security theatre, X-ray machines at the entrances to some (most?) lines but lots of people were just ignoring the attendants and walking quickly passed the machines without having their bags checked.

Yes, that’s the main difference between Beijing and Shanghai’s metro system. In Beijing, there is no way to avoid security check and everyone obeys, while Shanghai didn’t enforce that and everyone learned to ignore that.

Then again, there are people arguing that the security measures in neither systems are very effective.

That is just China in general. Their only card based payments for quite some time was UnionPay. Many places were cash only though. In the past 2-3 years electronic payments through WeChat or Alipay have absolutely exploded and nearly every business accepts it as payment in major cities. Unfortunately as a westerner these payment methods are mostly inaccessible, so cash payment remains the only feasible way to pay for most things.

It always makes me think about how when cities or nations get more wealth, they seem to value different things. Wealthier East Asian cities consistently have great public transport.

Is it just a population density thing, that there's so many people zipping around in such a small area that it pays off to spend the money on infrastructure? Is it a lower cost of labour thing? Or is it a thing that people value more and demand? I'm never quite sure.

> It seemed difficult (impossible?) to pay with anything but cash

That's true and it is not convenient for visitors. Local people usually just use public transportation card (magnetic/contact-less smart card) everyday and don't have to pay with cash (you can charge the card with credit card or Alipay). Some station gates also support paying with NFC smartphones (eg. Xiaomi), and I think that's modern :-)

It's not too hard, with a bit of diligence (and a phrasebook), to get a contactless card as a foreigner. Although it is still easiest to add value with cash through one of the station attendant booths.

I usually find cash annoying, but as the fares are so ludicrously cheap (3-6 yuan), when I was there I didn't find it so much of an issue.

One thing that I didn't like about the Shanghai metro was the fact that it closes at like 11pm, but other then that it was a very good experience