The two Koreas have been striving to improve relations since the breakthrough six-nation talks in February, involving North and South Korea, China, Japan, Russia and the United States, when Pyongyang agreed to dismantle its nuclear program for aid, energy supplies and security guarantees.
The trains carried 150 passengers on a test run, largely politicians and journalists from both sides, and also a conductor from one of the last trains that made the crossing before the rail link was severed in 1951.
North and South Korea re-linked their railways on June 14, 2003 on two sections of a 4 kilometer demilitarization zone, which divides the peninsula along the 38th parallel. Seoul and Pyongyang were to test the railways last May, but the arrangements were never conducted because the militaries of both sides failed to ensure security guarantees.