In the Korean War China and North Korea fought together against the United States. Frontline needs in tens of thousands tons of military supplies every day. Railways has become the most important means of transport. The U.S. Army, unwilling to accept defeat on the battlefield, mobilized a large number of aircraft to bomb indiscriminately along railways, and carried out the so-called "war of attrition". Following the order of Commander Peng Dehuai, Liang Junying, the commander of the Sino-DPRK Joint Railway Transport Command, led the volunteer warriors on the transport front to carry forward the fearless revolutionary spirit, building bridges, repairing railways, and transporting supplies in the "317" section, which was dotted with bombs and mines. This is the real "indestructible and bombable steel transport line".