None of which should detract from the powerful symbolism of a meeting between the leaders of two countries whose wildly different political systems and economic fortunes belie strong cultural and familial ties.
Official talks between Mr Moon and Mr Kim will begin at 10:30am local time, at the Peace House in Panmunjom.
At the end of talks, Kim and Moon will sign a pact and make an announcement, Im said.
A study published last month by the journal, authored by a team led by Liu Junqing at the quake bureau in Jilin province along the border with North Korea, found similar results of the September 3 explosion.
The crash has sparked a series of rare mea culpas on North Korea's tightly controlled propaganda network in which Kim has taken centre stage both in responding to the crash and apologising to China. Trump said his meeting with Kim may happen in May or early June.
After the welcoming ceremony, the two leaders will move on foot to the Peace House, a venue for the third inter-Korean summit since the first in 2000 and the second in 2007 were held in the DPRK's capital of Pyongyang.
The train left at midnight, with high-level North Korean officials aboard along with China's ambassador and medical experts, said Chinese foreign ministry spokeswoman Hua Chunying.
However, Seong's daughter Jeon Hyo-ju, a 23-year-old university student, told the Mainichi Shimbun, "Honestly, I haven't been interested in the leaders' summit".
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Thailand is willing and able to host a meeting between U.S. President Donald Trump and North Korean leader Kim Jong Un, but no plans have been made to do so, the country's foreign minister said Tuesday.
He is ruthless enough to have had relatives executed but now feels secure enough in power to gamble on Trump, they said.
The information the world receives will also be closely controlled: Except for a group of pool reporters at the summit, whose access may be extremely limited, journalists will be sequestered at a media center well away from heavily guarded Panmunjom, the border village where the summit will take place.
More recently, many US experts were caught off-guard by how nimbly Kim shifted from his saber-rattling drive to build a nuclear missile arsenal to diplomatic outreach. A banquet and farewell ceremony will follow in the evening before Mr Kim returns to the North.
"It is especially tricky as the issue isn't something the South-North summit can wrap up", Im said.
The two leaders will then go for a short, informal walk before resuming talks.
"Perhaps the North Korean nuclear weapons problem can be solved through dialogue", said Seong Sun-gi, a 53-year-old Seoul housewife.
North Korea's nuclear tests are of special concern to Beijing, since the test site near the town of Kilju is less than 100 kilometers (60 miles) from the border with China.