The trip, which is part of a joint study to inspect the old rail system of the North, follows a series of summit summits between leaders of the two countries earlier this year to encourage the North to abandon its nuclear weapons program.  Alternative fuels remaining from the journey must be returned to South Korea to avoid inspectors disregarding international trade restrictions in the north of the country.
South Korean President Moon Jae-in has long dreamed of building a Trans-Korean railroad. During a speech last year, he pledged that the "severed inter-Korean railroad will be reconnected," adding that one day a train leaving from Busan and Mokpo drives through Pyongyang and Beijing, heading for Russia and Europe ,
A seven-car train left Seoul Station on Friday at 6:30 am local time and arrived at the border two and a half hours later.
As the inspectors proceed slowly and cautiously, they hope to ascertain the condition of the North Korean railways and how much money they will need to carry them to the point the they need South Korean trains.
According to South Korean officials, North Korea has more than 5,226 kilometers of railroad, compared to 3,900 kilometers in the south. However, most North Korean routes operate as single-track routes (ie trains can not move past each other) at an average speed of 40 to 50 km / h.
Korail from South Korea estimated the total in 2012 The cost of repairing the railways in North Korea was $ 210 million for the eastern line and $ 96 million for the western line, although these figures have since been due to persistent shortages Repairs and the impact of sanctions. For the first time, a South Korean railcar has driven along the eastern Donghae Line of the north from Mount Kumgang to the Tumen River.
South Korean inspectors visited the north in 2007 to investigate the Sinuiju-Kaesong section during a rapprochement phase.
The new voyage will travel from Kaesong to Sinuiju near the border with China down to Pyongyang, Wonsan and Anbyon before reaching the Tumen River and returning to Seoul via Wonsan, Pyongyang and Kaesong.
Jong-il, head of the joint survey team, was also part of the 2007 inspection, which was conducted in the bitter Korean winter.
"(It was) very cold." When we were traveling by train, we had to do our survey while occasionally avoiding the train from the opposite direction, which was difficult, "he told reporters.
At least this time, the train is continuously heated so inspectors can focus on the tracks instead of focusing on keeping warm.
"The team members are experts in the field so they can recognize aging for most parts, and the outcome will depend on how much the North Korean officials will show us," Im said.
Headache in Sanctions
But while the two Koreas are slowing down the buildup of stronger relations, the North remains exposed to stringent international sanctions on its nuclear and missile tests.
The Trump administration also commented on the prospect of South Korea promoting inter-Korean projects, claiming that sanctions are an important diplomatic tool to hold the North accountable.
The team had to receive special permission from the United Nations to conduct the visit and is under strict instruction to bring any remaining material to Seoul.
] The sanctions have created a series of problems for South Korean inspectors who have had to bring their own food, water and fuel so they do not violate sanctions when buying from the North. The inspection team is also wary of the health risks of drinking or consuming North Korean products.
"There was a lot of abdominal pain in the last survey (in 2007), so we bring a lot of water," said Project Manager Ji Yong-tae.
A pool reporter who had boarded the train before leaving said hundreds of water bottles were stacked in one of the compartments next to the two-meter-long sleeping capsules where the inspectors would be living in the next few weeks.