Having recently done it, what really stands out about the Pyongyang metro is that it really isn't that different from any other metro in the world, although, as with other things in NK has a number of strange quirks. The stock receives a "star" for successful completion of 50,000 miles service and a large collection of stars seen as a positive accolade rather than the fact the stock is very old!
It was very surprising how much freedom we were given, and I'm entirely convinced we were travelling on ordinary service trains. We travelled from one station to another, disembarked, and then travelled on another train several trains later to another station several stations on. Every train we saw, and the stations themselves were really busy - equivalent to London middle-of-the-day busy. The stations we stopped at were elaborately decorated, and well appointed. The stations we didn't stop at didn't look as lavishly decorated, but looked in just as good nick as the London Underground.
There are an awful lot of staff, but no more so than in most Chinese metro systems.
If you ever get the chance, go... North Korea is quite certainly the weirdest place you'll ever visit, and, while I wouldn't swap my life for that of a North Korean, the leadership is evil, and they are deprived of a lot of freedoms, most of the supposed weirdness of the place is made up by the western / South Korean press and isn't a reflection of reality.