38North, the Washington think tank, cautioned that the train’s presence “does not prove the whereabouts of the North Korean leader or indicate anything about his health”.
“But it does lend weight to reports that Kim is staying at an elite area on the country’s eastern coast,” it said.
The North Korean government has not responded to reports about Kim’s health, while the country’s media has not mentioned his health or whereabouts.
Kim hasn’t been seen in public since April 11, sparking speculation that the 36-year-old might be seriously ill.
Rumblings have intensified since Kim failed to appear publicly on North Korea’s most important holiday on April 15.
Daily NK, a South Korean online publication, reported that the North Korean leader underwent a cardiovascular procedure on April 12 that involved putting a stent into one of his arteries.
Japanese magazine Shukan Gendai reported a Chinese doctor was sent to North Korea to treat the leader after a delay in the procedure resulted him falling critically ill.
A Chinese medic reportedly told the magazine that Kim clutched his chest and fell to the ground on a visit to the countryside.
A source within the Australian government said it was monitoring intelligence on Kim’s health and leaning towards the dictator being in some kind of trouble, but there was no clear determination.
There are concerns within the Australian and US intelligence communities about who would succeed Kim if he was critically ill. The concern is heightened by the fact the potential upheaval in the North Korean regime would take place while the rest of the world is battling outbreaks of the coronavirus.
Kim’s younger sister, Kim Yo-jong, would be among the candidates to take the job.
Believed to be in her early 30s, she is a somewhat mysterious figure, with basic details like her exact age unconfirmed by the North Korean regime.
US President Donald Trump hosed down reports that Kim was gravely ill last week at a White House briefing, saying “I think the report was incorrect”.
Mr Trump has met Kim three times as part of his mission top convince the North Korean leader to give up his nuclear weapons program, and has called him a friend.
Kim has been in power since 2011, when he took over after his father Kim Jong-il died.
Anthony is foreign affairs and national security correspondent for The Sydney Morning Herald and The Age.