HANOI (Reuters) - North Korean leader Kim Jong Un’s trip to Vietnam for a summit with U.S. President Donald Trump was shrouded in mystery until a green train with yellow horizontal stripes was spotted crossing the Yalu river into China on Saturday evening.

Workers are seen at the Dong Dang railway station where North Korean leader Kim Jong Un is expected to arrive, at the border town with China in Dong Dang, Vietnam, February 24, 2019. REUTERS/Athit Perawongmetha

Kim, his father and grandfather, North Korea’s three leaders in succession since World War Two, have all loved trains, but no one knew how Kim intended to make the journey to Hanoi for his second summit with Trump, on Wednesday and Thursday, until the train rumbled over the border bridge.

It is not clear if Kim will travel all the way to Vietnam by rail - it will take him some two and a half days to do so - and it is possible he could stop on the way and fly.

If he does choose to stay on the tracks, he will be traveling in style.

His train resembles the armored ones his father, Kim Jong Il, and grandfather, Kim Il Sung, used over the years.

It has 21 carriages equipped with all-white conference rooms, dining cars and sleeping quarters.

Some carriages are decked out with pink leather chairs, big-screen televisions and ivory-colored curtains hanging in the windows, North Korean state media has shown.

The train also has satellite phone connections so Kim can keep abreast of developments and issue orders, according to state television.

It also has a carriage loaded with his Mercedes Benz vehicle, South Korea’s Joong Ang Ilbo newspaper reported.

“His private train for sure has a luxurious interior and good-quality facilities, but it also can travel safely in China, with pretty good rail tracks there,” said Ahn Byung-min, a senior analyst at South Korea’s government-funded Korea Transport Institute.

The train can reach speeds of up to 80 kph (50 mph) on China’s network, compared with a maximum of about 45 kph (28 mph) on North Korea’s tracks, Ahn said.

PEACE TRAIN, WAR TRAIN

While Kim is taking the train to make peace this time, he has in the past used the same train to prepare for war.

In 2016, state media showed him arriving back in Pyongyang in triumph, to a red-carpet celebration at Pyongyang station, from a satellite launching station in Sohae, after the successful testing of a long-range rocket that the United States said was an inter-continental ballistic missile.

During a summit with South Korean President Moon Jae-in in Pyongyang in September, North Korea pledged to dismantle key missile engine-testing and launch facilities at the Sohae site, and recent satellite imagery has shown that has begun.

Trains have become part of the Kim family lore.

In late 2011, Kim’s father, Kim Jong Il, died on a train. The carriage, painted in the same green color, is exhibited in the Kumsusan Palace of the Sun where Kim Jong Il is lying in state.

North Korea’s founding leader, Kim Il Sung, Kim’s grandfather, traveled abroad by train regularly during his rule until his death in 1994.

His train journeys included a trip to Vietnam in 1958 when he transferred in Beijing to a plane, and travel to Eastern Europe in 1984, via the Soviet Union.

In the 2002 book “Orient Express”, Russian official Konstantin Pulikovsky described Kim Jong Il’s three-week journey to Moscow.

In the train, which was a gift from Soviet leader Stalin, cases of Bordeaux and Beaujolais were flown in from Paris, as was live lobster, according to the book.

Nam Sung-wook, a former South Korean intelligence official, said Kim’s decision to travel to the summit by train was part of an image he wanted to project.

“Kim Jong Un is already putting on a big show, opting for more than a 60-hour train journey, when he can get to Hanoi in just four hours by flight,” Nam told Reuters.

“Pageantry is already winning over substance in this summit.”