This is fascinating -- it was certainly long reckoned, in the not-very-distant past -- backed up by the odd tantalising "encounter" -- that North Korea's railways had some steam locos in genuine commercial use; but said country, must always have been one of the world's least-favourable / possible for foreigners to wander around in ad lib, trying to discover things. There took place in past decades, some actual organised railway-enthusiast tours in NK -- the one-time undertaking
To Europe For Steam was a prominent "player" therein; but those in control in that land, totally "call the tune" vis-a-vis all such things: from reports of these tours, it would appear that the steam action very much revolved around specials laid on for the groups -- using steam locos which also ran in genuine everyday commercial service, but witnessing of those everyday doings was not "on the menu". It would appear that such happenings likely still occur -- as per
@Vespa above, seemingly in a highly specialised situation.
There comes to mind, that there is presumably a matter of break-of-gauge between Russia (1520mm), and Korea ("four-eight-and-a-half"); one wonders quite how that is handled, for freight traffic -- the "steam factor" perhaps involved there?.
Whimsically -- with North Korea's notoriety for all manner of sinister and outlandish goings-on: the notion crosses the mind, of "mad scientists / thought police" there, having developed who-knows-what scary techniques to achieve their malign ends: could they have perhaps been messing with the journalist's head so that he thought he was hearing / seeing a steam loco, when in fact it was just a boring diesel...?
