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 Wednesday. The trips will be used for a study to assess what is 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.