text: Chapter 5
  Defense and Large-Scale Combat Operations in the Pusan
  Perimeter
  On June 25, 1950, the 89,000 strong North Korean People’s Army (NKPA) invaded the
  Republic of Korea (ROK) and quickly overwhelmed the ROK units. Throughout July,
  NKPA units pushed southward as the ROK army and recently arrived American units
  fought to slow their advance. By August 4, Eighth Army Commander, Lieutenant
  General Walton H. Walker, had established the 140-mile Pusan Perimeter which halted
  the NKPA. Walker’s defensive line depended on holding the road and rail network that
  supplied the front. Over the course of the next 45 days, Walker had to hold the
  perimeter while his logistical support units re-established combat power to transition to
  the offensive and breakout of the perimeter.
  The Pusan Logistical Command, established by Walker, served as the principal
  sustainment organization providing for all sustainment functions throughout the Battle
  of the Pusan Perimeter (August 4 - September 15). This logistical command centered
  on Pusan harbor, the most developed and biggest harbor on the peninsula. It was the
  center of the supply effort for United Nations forces within the Pusan Perimeter. Its four
  piers and intervening quays could berth 24 or more deepwater ships and could handle
  a capacity of 45,000 tons daily. Pusan also had a good transportation system of
  railroads running from the port to points north; it formed the backbone of the
  transportation system in Korea. On August 30, the 714th Transportation Railway
  Operating Battalion arrived in Korea and became responsible for operating the 500
  miles of railway line within the Pusan perimeter.
  Necessary munitions for the build-up came either from Japan, as part of the
  refurbishment operation for WWII vehicles and munitions, or shipped directly from the
  United States. By August, an average of 4,000 vehicles a month cleared the repair
  shops in Japan and were transported to Pusan through an expedited rail-shipborne
  system to deliver them in two days. Additionally, the Army shipped equipment from the
  Continental United States. In early August, a cargo ship arrived with 80 U.S. medium
  tanks capable of defeating the NKPA’s T-34 tanks. By the third week of August, through
  resupply and the deployment of armor units, American tanks outnumbered the NKPA
  tanks by at least 5 to 1.
  To provide health service support for the high rate of casualties among American and
  ROK forces, the Army established Mobile Army Surgical Hospital (M.A.S.H.) units. The
  8055th M.A.S.H. was assigned to the 24th Infantry Division in July. Shortly thereafter,
  the 8063rd and 8067th began operations within the Pusan Perimeter. These units often
  received 100-200 casualties per day. From these units, hospital trains returned
  wounded soldiers to Pusan for further care. To provide for Class I supply, the Army
  had to rely on WWII-era K-rations available in Japan. None of the new C-rations were
  immediately available. The Quartermaster General issued orders that all available C
  rations in the U.S were to be immediately shipped to Korea to feed U.S. and ROK
  personnel.
  By September 1, United Nations Command (including ROK and British troops) had
  180,000 men based in the Pusan Perimeter. Shortly after the landings at Inchon on
  September 15, Pusan Logistical Command was redesignated as the 2nd Logistical
  Command for the remainder of the war. On September 20, American and ROK units
  began to move forward and two days later, Walker issued his operations order for a
  full-scale breakout of the Pusan Perimeter.