North Korea is one of the most secretive countries in the world, and the truth about Thursday's explosion is only slowly starting to emerge.
On Saturday, the North Korean news agency KCNA broke its silence 48 hours after the blast at Ryongchon station.
The accident had been sparked by "an electrical contact caused by carelessness during the shunting of wagons loaded with ammonium nitrate fertilizer", it said.
But prior to the announcement, rumours had abounded to fill the vacuum.
The incident came just hours after North Korean leader Kim Jong-il is believed to have passed through the town of Ryongchon on his way home from a trip to Beijing.
The North Korean leader's train passed through hours earlier
The timing triggered suspicions that the explosion could have been part of an assassination attempt on Mr Kim.
A reporter for the South Korean newspaper Kyunghyang Shinmun said a colleague had spoken to a North Korean policeman in Dandong, about 20km (12 miles) from Ryongchon, who said that the authorities were not treating it as an accident.
But South Korean intelligence source have said there were no signs of sabotage.
South Korea's Unification Minister, Jeong Se-hyun, has referred to the crash as an "accident".
Even if the explosion was not a direct attempt on Mr Kim's life, the commotion caused by his travel through Ryongchon may have contributed to the crash.
North Korea analyst Aidan Foster-Carter told the BBC that the country's poorly maintained rail infrastructure would have come under further strain while Mr Kim was travelling, as signals and timetables changed to accommodate his special train.
Early South Korean media reports said that two trains, carrying petrol and liquefied gas, collided, fuelling an explosion at Ryongchon, 20km from the Chinese border.
According to South Korea's Yonhap news agency, there were even rumours that the fuel on board the trains was a gift from China to Kim Jong-il and his energy-starved country.
China's official Xinhua news agency said the accident was caused by ammonium nitrate leaking in one of the trains.
Ammonium nitrate is used in its fertilizer grade in the agricultural industry, and in a higher grade in the explosives industry, including mining.
The Red Cross and the World Food Programme, both operating out of North Korea, also said the trains involved were carrying explosives, similar to those used in mining.