More than 400 people were killed in a train derailment that took place in North Korea last month, according to Radio Free Asia (RFA) on Jan. 16.

According to an unnamed source cited by the RFA, a passenger train traveling from Pyongyang to Kumgol, South Hamgyong Province, suffered a derailment on Dec. 26 due to a sudden power shortage while traveling up a steep slope.

The RFA reported that the train at the time had departed Tanchon Station and was traversing a steep slope 700 meters (2,296 feet) above sea level between Dongam and Ripa stations.

According to the RFA’s source, the train’s traction voltage weakened as it ascended toward Ripa Station, and the resulting loss of power caused it to lose speed and eventually slide backward.

The source said that the train driver tried to brake, but the train continued its slide downhill, leading seven carriages to detach and roll down the mountain.

While the engine and the two upper-class carriages immediately behind it — which carried mostly high-ranking officials — remained on the tracks and later arrived safely at Tanchon Station, the majority of passengers inside the seven carriages that derailed were killed in the incident, according to the RFA’s source.

The source estimated that approximately 400 passengers were killed in the derailment, based on the seating capacity of North Korean passenger trains and the casualties witnessed by local residents.

The source also told the RFA that passengers aboard the derailed carriages consisted mainly of young men headed for the Komdok mines in the Kumgol area and middle-aged women traveling to make ends meet.

“Those who were severely injured were rescued from the site and taken to a hospital in Tanchon, but most of them died in the hospital,” the source said, adding that North Korean authorities set up a task force to probe the causes of the accident and remove bodies from the site.

The RFA’s report on the incident bears similarities to a previous accident that took place on the same steep railway near Tanchon in November 1998, as well as another derailment in November 1995 near Chongjin, North Hamgyong Province, that was recounted by a defector in Barbara Demick’s “Nothing to Envy.”

In the latter incident, the defector recalled the crowded back carriages were also almost entirely destroyed and that hundreds of their passengers had been killed, but that the front cars had been spared.

The North Korean rail network is believed to transport about 90 percent of regime’s freight, but is reported to be in poor condition and suffering from chronic power shortages, with dilapidated rolling stock only able to run at 65 kilometers (40 miles) per hour or less.

Although the North Korean state media covers industrial accidents and mass casualty incidents in South Korea in great detail, it typically does not report on similar events inside the country, making it difficult to confirm the recent derailment’s occurrence.

But the accident, if it did occur, may have prompted leader Kim Jong-un to call on regime officials to “elevate the safety of rail operations” during his remarks at the Supreme People’s Assembly on Monday.

Some details in the RFA’s report also did not align with known information.

While the RFA reported that the recent derailment took place during heavy snowfall on Dec. 26, the South Korean national weather agency’s data shows clear and relatively warm weather in the region between Tanchon and Kumgol in that time frame.

In response to the RFA’s report on the incident, Seoul’s National Intelligence Service said it is “still working to confirm details,” while the Unification Ministry said it has “no verified information to share at the moment.”

BY MICHAEL LEE [lee.junhyuk@joongang.co.kr]