In the past year or so, automated ticket-vending machines have sprung up on the Beijing subway network. I hadn't had to bother about them much (60 or 70% of them seemed to be 'out of service' at any given time anyway), but both of my pre-pay subway cards crashed on me recently, within a few days of each other (mysteriously irradiated by a passing UFO??), wiping off a small but irksome amount of remaining credit in both cases - and I gather there is only one place in the whole of Beijing where you can attempt to replace a faulty card and get your deposit transferred over to a new one (yes, it's only 30 kuai, but it's the principle of the thing!).
I haven't yet got around to that; so, for the past two or three months I've become a regular user of the vending machines.
Luckily, not too many other people seem to be (as yet); so it's actually a fairly swift and painless method of procuring tickets for travel. Except that.....
Well, the touch-sensitive menu screen can be maddeningly glitchy. It appears to utilise body heat. So, when there's 20 degrees of windchill.... it DOESN'T WORK.