| A South Korean train crossed into North Korea on Friday for the first time in a decade - packed with engineers on a mission to determine how to upgrade the North's two dilapidated railways that create a linked, cross-border network.
An agreement to connect the railway systems was made earlier this year in a key meeting between North Korean leader Kim Jong-un and the South's President Moon Jae-in.
TV footage on Friday showed a red, white and blue train - displaying a banner reading "Iron Horse is now running toward the era of peace and prosperity" - pull away from the South's Dorasan station, the nearest terminal to the western inter-Korean border.
"This signals the start of co-prosperity of the North and the South by reconnecting railways," Transport Minister Kim Hyun-mee said.
She added that reconnecting the railway would help expand the country's "economic territory" overland to Eurasia, as the divided Korean peninsula has left South Korea without a land route to the continent for many decades.
The six-carriage train carried 28 South Koreans onboard including railway engineers and other personnel. It was also carrying 55 tons of fuel and an electricity generator.
There is a passenger coach, a sleeping coach, an office and a carriage loaded with water for showers and laundry.
When it arrived at Panmun Station - the first North Korean terminal across the border - the six carriages were hooked to a North Korean train.
The South Koreans and their counterparts will live on the train, while they inspect two railway lines - one linking the North's southernmost Kaesong City to Sinuiju City near the Chinese border, and another line that connects Mount Kumgang near the inter-Korean border to the Tumen River bordering Russia in the east. The inspection will last 18 days and they will travel some 2,600 kilometers by rail, the transport ministry said.
Before the division of the Korean peninsula in 1948, there were two railway lines linking the North to the South - one in the west and the other in the east.
As a gesture toward reconciliation, the two Koreas reconnected the western line in 2007 and limited numbers of freight trains that transported goods to and from the Seoul-invested Kaesong industrial zone in the North for about a year. But the line has since been out of service due to tensions over the North's nuclear development program.
The current railway project has also faced delays over concerns it could violate UN sanctions imposed on the North over its nuclear and missile programs. But the UN Security Council granted an exemption for the joint study last week.