Kim Jong Un’s gift of two hunting dogs to South Korea in September is starting to bear more fruit, first with a litter of puppies and now with a landmark railway deal.

South Korea will send trains across the border to North Korea for the first time in a decade after the United Nations Security Council granted exemptions from sanctions, Seoul said today. The trips will be used for a study to assess what’s needed to connect one other railway that has been separated since the Korean War.

The development shows that South Korean President Moon Jae-in is making steady progress toward his goal of achieving “irreversible progress” on inter-Korean relations by the end of 2018. Earlier this month, his office disclosed pictures of six puppies delivered by one of the North Korean dogs.

“Six were added to the gift of two, which is great luck,” Moon said in a Nov. 12 tweet, shortly after he sent 200 tons of tangerines to Pyongyang as a gift. “I hope North and South Korean matters would be just like that.”

Still, Moon can’t go too fast. U.S. President Donald Trump has insisted that sanctions stay in place until Kim’s regime completely gives up its nuclear weapons. With a second summit between Trump and Kim now in doubt, Moon has stopped openly promoting potential economic benefits of greater engagement with North Korea.

Moon “needs to build the foundations for inter-Korean reconciliation to continue once he leaves office,” said Ramon Pacheco Pardo, Korea Chair at the Institute for European Studies in Brussels. The current administration “will continue to test the waters in the coming months, and will also ask for waivers and use aid to slowly strengthen inter-Korean economic links.”

Here are areas of cooperation that Moon and Kim promised to make progress on this year.

Military De-escalation

As part of a military agreement to reduce accidental border clashes, the two Koreas each destroyed 10 guard posts, enforced a ban on military exercises in the area and imposed a no-fly zone. Last week, military officials from the nations put their guns down and shook hands to discuss connecting roads to jointly excavate remains during the Korean War.

Restoring Communications

Military officials from both sides also restored fixed-line phone and fax machines by upgrading to fiber-optic cables from copper, and government officials are working on improving the communication lines. They also opened a venue for around-the-clock communications: A liaison office in the border town of Gaeseong.

Connecting Rails, Roads

Seoul and Pyongyang will begin a joint survey of the North Korean rail system on Friday for about 18 days. The neighbors have also discussed reconnecting roads and starting direct flights. Those moves, however, would require exemptions from sanctions that ban shipments of fuel or activities that could generate revenues for Kim’s regime.

“Should South Korea request some sanctions relief aimed at economic aid that is part of inter-Korean easing, the U.S. should be able to live with that,” said Stephen Noerper, senior director at the Korea Society in New York. “North Korea has to show progress to give Moon the political space he needs to proceed.”