Complex sentence: It is located on the Pyongbu Line, which was formed from part of the Kyongui Line to accommodate the shift of the capital from Seoul to Pyongyang; though this line theoretically connects Pyongyang to Pusan, in reality it ends at Kaesong due to the Demilitarized zone.
Split into simpler sentences: It is located on the Pyongbu Line, which was formed from part of the Kyongui Line to accommodate the shift of the capital from Seoul to Pyongyang. Though this line theoretically connects Pyongyang to Pusan, in reality it ends at Kaesong due to the Korean Demilitarized Zone.