To facilitate the construction of the Sŏhae Satellite Launching Station, the Ch'ŏlsan Line was extended in the early 2000s to the launch facility via Ch'ŏlsan and Tongchang. On 22 April 2004, the worst railway disaster in the DPRK occurred when a train carrying ammonium nitrate fertiliser exploded at Ryongch'ŏn Station.