A South Korea train rolled past the demilitarized zone into North Korea on Friday, marking the first time it's been done in more than a decade.

Aboard was a team of rail experts from the South that will be inspecting ways for the North to modernize its rail network in hopes that someday both countries will connect, making travel and trade easier across the border.

The weekslong inspections represent one of the most significant goodwill gestures between the Koreas in past months as they push ahead with engagement.

The plan to modernize North Korea’s outdated railways and roads came from the historic meeting between the two country’s leaders in April, in which North Korea’s Kim Jong-un asked for help with updating the country’s “embarrassing” railway network.

A South Korea train is prepared to travel across the border into North Korea at the Dorasan Station in Paju, South Korea, Friday, Nov. 30, 2018. (Jeon Heon-kyun/Pool Photo via AP)

"Through the railways that will be connected in one, the South and North will prosper together and peace in the Korean Peninsula will become firmer," South Korean Unification Minister Cho Myoung-gyon said during a ceremony at Dorasan Station near the border. "We will maintain close consultation with related nations so that the project to connect the South and North's railways could proceed with international support."

The South Korean engineers boarded the train in Dorasan, just north of Seoul, on Friday morning. A banner displayed across the train described it as an “Iron Horse” running towards an era of peace and prosperity, the BBC reported.

At Panmum Station, near the town of Kaesong, a North Korean engine took over to pull the train further north.

A South Korean soldier stands guard next to the rails which lead to North Korea, inside the demilitarized zone separating the two Koreas in Paju, South Korea Friday, Nov. 30, 2018. (Kim Hong-Ji/Pool Photo via AP)

According to plans outlined by Cho's ministry, Korean officials will begin by surveying a 248-mile railroad section between Kaesong and Sinuiju that cuts through the North's central region and northeastern coast.

From Dec. 8 to 17, the Koreas will inspect a 497-mile railway section along the country's eastern coast, stretching from an area near the scenic Diamond Mountain to a riverside station near the North's border with Russia.

During the surveys, a North Korean train engine will pull six South Korean cars — including passenger and sleeping cars, a power-generator car and a fuel tanker — to test operability.

The Unification Ministry said the North will attach its own cars to the engine, but it was unclear how many. Fifty-six South Korean officials will participate in the surveys, 28 each for the inspections on the western and eastern sections, the ministry said.

A South Korean train runs on the rail track, which the two Koreas hope to eventually use as an international transport link, near to the border village of Panmunjom in North Korea, in Paju, South Korea, Friday, Nov. 30, 2018. (AP Photo/Ahn Young-joon)

The Koreas plan to hold a groundbreaking ceremony by the end of the year on an ambitious project to connect their railways and roads as agreed by their leaders. But beyond surveys and tape-cuttings, the Koreas cannot move much further along without the removal of U.S.-led sanctions against the North, which isn't likely before it takes firmer steps toward relinquishing its nuclear weapons and missiles.

Also on Friday, an official from Seoul's Defense Ministry said the North and South Korean militaries completed removing 20 front-line guard posts and landmines from a border area where they plan to start their first-ever joint search for remains of soldiers killed during the 1950-53 Korean War. The official spoke on condition of anonymity, citing office rules.

The joint railway surveys were on hold before the U.N. Security Council on Saturday granted an exemption to sanctions that allowed them to proceed. Seoul initially said the joint surveys wouldn't violate U.N. sanctions but later said that Washington had different views and the two sides had discussed the matter.

The Associated Press contributed to this report.