cargo and almost 1,000,000 troops. The Japanese National Railway, first under direct MRS control and later under commercial arrangements, met our demands on it rapidly and efficiently. In addition, military air transport based in Japan provided invaluable support to the fighting forces, air-landing and air-dropping supplies, moving airborne forces, evacuating the wounded, and returning personnel for rest and recuperation. In the beginning the water movements from Japan to Korea were unregulated, resulting in sporadic arrivals at receiving ports and necessitating the use of emergency and express shipments. Beginning in the summer of 1951 a cargo movements program was instituted, and was subsequently expanded and strengthened. The resultant improvement in preplanning of requirements and in the utilization of shipping made possible the ultimate discontinuance of the expensive expedited railwater (Red Ball) service previously in effect. Concurrently efforts were made to ship at least fifty percent of the Korean requirements directly from the Zone of Interior, a goal that was realized in the latter phases of the war. and However, the worst transportation difficulties were in Korea. Port facilities were inadequate; means of interior transport were even more so; operations were further complicated by adverse climate, mountainous terrain, the alternate destruction and rehabilitation of port and rail facilities, the crowding of logistic installations in the Pusan area, and the lack of adequate intransit storage between Inchon and the forward areas. In the course of the conflict, over 13,000 Transportation Corps port, harbor craft, DUKW, railway, truck, transport helicopter, and traffic regulating troops were placed in service in Korea. Augmented by thousands of indigenous personnel, they succeeded in doing the job. During the war and its immediate aftermath, the Army-operated ports in Korea handled a tremendous volume of traffic. In the period July, 1950-December, 1953 they discharged more than 38,000,000 measurement tons and backloaded 9,369,000 measurement tons. The bulk of this traffic flowed through Pusan and Inchon. Other ports used included Kunsan, Masan, Sokcho-ri, Chumunjin, Koje-do, and Chogu-ri. Under the control and supervision of the 3d Transportation Military Railway Service, the battered lines of the Korean National Railways were converted into the principal means of inland transport between the ports and the fighting forces. Additional rolling stock and locomotives were placed in service, car utilization was intensified, and operational and maintenance procedures were improved. Ultimately the MRS operated more than 10,000 cars and 460 locomotives over 1989 kilometers of rail line. Indicative of its accomplishment was the doubling of the total tonnage forwarded from the port areas between July 1951 and November 1952. Despite rugged terrain and extremely poor roads, which made long hauls impracticable, motor transport played an important role in the support of operations. Transportation Corps trucking units were employed for port clearance and base hauling and, in the combat zone, for transport between forward railheads and Army supply points and for effecting tactical troop movements laterally across the front. In the single month of May 1953, Transportation Corps vehicles handled 9,708,000 cargo ton-miles and 4,530,000 passenger-miles. Many other forms of transport were used. In some areas Korean porters, carrying supplies on A-frames strapped to their backs, provided close support for the combat forces. A more modern means of overcoming terrain obstacles was provided late in the war with the arrival in Korea of two transport helicopter companies. In actual operations and in realistic field exercises the helicopter units demonstrated their ability to effect tactical moves, to provide logistical support, and to accomplish frontline evacuation of the wounded in areas inaccessible to other means of transport. Coastwise shipping was employed for the supply of Republic of Korea forces on the eastern front via Sokcho-ri. Air transport was utilized for intra-Korea movements and for movements between Korea and Japan. Pipelines were initially limited, but with new construction became increasingly important in the latter part of the Korean conflict. At the end of hostilities more than 400 miles had been placed in operation for the supply of airfields and other installations. During and after the Korean War the Transportation Corps continued its support of our oversea forces throughout the world, and undertook several new or expanded activties. In Europe, Corps personnel handled Army traffic via the Bremerhaven supply line, and helped to develop and maintain an alternate line of communications across France. They participated in continuing "over-thebeach" exercises held off the French coast. Progress was made in emergency planning for the coordinated use of transportation facilities at the NATO and SHAPE levels. Through the in creased use of Transportation Corps officers with military advisory groups, valuable technical assistance has been rendered to our allies in many areas of the world. Under arrangements initiated in 1951 and formalized in 1954, the Corps undertook the worldwide operation of oversea water ports in support of the Air Force. Stevedore and lighterage troops were provided also for annual Alaskan resupply missions and, beginning in 1955, to support the construction of the Distant Early Warning net across the rim of the North American continent. Furthermore, mass off-the-road hauling tests and operations have been conducted on the Greenland ice cap since 1952, and more recently in the Antarctic. THE CHALLENGE OF THE FUTURE Continuing international tensions, and the revolutionary changes in weapons and tactics which are now going on, have imposed challenging tasks on the Transportation Corps and on all military transportation agencies and facilities. While adjusting to declining workloads and to money and manpower limitations, the Corps has sought to meet the Army's needs for far greater mobility and dispersion in any future war, whether limited or general, atomic or nonatomic. Much headway has been made in tailoring the Corps' operations, equipment, training, organization, and doctrine to these requirements. Emphasis has been placed on increased capabilities for strategic, tactical, and organic airlift; for dispersed port and beach operations; for diversified and flexible rail and motor transport; and for mass off-the-road hauling. The handling and movement of cargo is being facilitated through the large-scale use of containers and pallets, and through the development of roll-on, roll-off vessels. To permit greater flexi bility in the management and use of CONUS ports, terminal command headquarters have been established on each of the three coasts. In addition, plans have been laid for the use of alternate ports and beaches in the event of the destruction of established terminals. Concurrently the Army as a whole has been coming to a fuller understanding of the vital importance of transportation, both for logistic support and to reduce vulnerability. In recent tactical reorganizations it has stressed air transportability and greater organic air and motor transport strength. For the first time a TC truck battalion has been made an integral part of the division. Concurrently a test, “Operation MASS” (see chapter 10), is being made of the feasibility of cutting down stocks held in forward areas by rapid transmission and processing of supply data and intensified use of fast transport. These are merely examples of the efforts being made, in many fields, to adopt our Army's transportation to the needs of the atomic age. Chapter 14 SIGNAL COMMUNICATIONS No military activity can be carried on successfully unless commanders, at every level, can promptly convey their orders to their subordinates and receive information from them. In the prescientific era this was accomplished by messengers, simple visual signals, and sound signals, (bugles, trumpets, horns, whistles, etc.). The development of electrical science and electronics has multi plied the possibilities of signal communications. Concurrently, however, the evolution of the military art, notably in the fields of wide dispersion and fast movement, has taxed those possibilities to the utmost. Atomic warfare, with its increased emphasis on mobility and dispersion, is further underscoring the need for signal communications which are reliable, secure, and adequate. DEFINITIONS AND TYPES Signal communications are defined as "the means of conveying information of any kind from one person to another, except by direct unassisted conversation or correspondence." The following means are used in the Army LINE/WIRE COMMUNICATION. It utilizes a physical path between sender and receiver, such as wire or a wave guide. RADIO COMMUNICATION. It utilizes radio waves not guided between sender and receiver by any such physical path. VISUAL COMMUNICATION. It utilizes optical signals, such as arm or flag movements, panels, lights, pyrotechnics, smoke signals, etc. SOUND SIGNALING. It utilizes various devices to transmit sound messages consisting of prearranged signals. (In an emergency the international Morse code may be thus used.) MESSENGERS. means of communication. They are in general human beings, traveling on foot, on horseback, or by sea, air, or land vehicle. (Pigeons and animals have also been used to carry messages.) Messengers are trained and used by military commanders at all levels as part of the unit's routine training and operations. The same is true of certain types of visual and sound signaling. As regards the more complex techniques, including line/wire and radio communications and allied applications of electronics, the equipment is provided by the U.S. Army Signal Corps, and the operating and maintenance personnel belong to, or are trained by, that Corps. It is with this field of signal communications that the present chapter is mostly concerned. (For further information on the Signal Corps see also chapter 2.) These are also a EVOLUTION OF SIGNAL COMMUNICATIONS Systematic progress in signal communication in our Army dates from the Civil War. CIVIL WAR. In that war, signaling by wigwag flags and torches was extensively used. Major A. J. Myer introduced insulated field wire and a portable electric set (the Beardslee magnetoelectric machine), perhaps the first such portable unit ever designed for military purposes. Its use in the war, however, was far overshadowed by another wire-telegraph organization, the U.S. Military Telegraph. This was a civilian organization, but it was controlled by the Secretary of War and officered by a few former telegraph company men commissioned in the Quartermaster Corps. Using commercial telegraph equipment (while adopting some of the field telegraph techniques which Maj. Myer had developed), it constructed, up to June 1866, a total of 15,389 miles of wire line for the Army, of which 1,000 miles were temporary field lines and 178 were submarine-cable lines. POST-CIVIL WAR PERIOD. The Signal Corps obtained control of Army telegraph lines soon after the war, and extended them to Army camps and posts throughout the western territories (later, from 1900 on, to the Alaska frontiers also). Possession of these lines by the Corps led Congress, in 1870, to assign to it the responsibility for national meteorological duties and daily weather reporting. While its telegraphers at Army posts throughout the country doubled as weather observers, the Corps, under the leadership of such pioneer meteorologists as Cleveland Abbe, created the first truly national weather service (transferred to the Department of Agriculture, as the Weather Bureau, in 1891). During the period of its weather service it contributed notably to the First Polar Year, 1882-3 (actually the first "international geophysical year"), sending scientific observers to Point Barrow, Alaska, under Lt. P. H. Ray (1881-3), and to Ellesmere Island, northern Canada, under Lt. A. W. Greely (1881-4). In the late 1870's the Corps used heliograph signaling. Following Bell's invention it adopted the telephone. Balloons for observation and signaling became a Corps responsibility about 1890. In the Spanish-American War the Corps used both telephone and telegraph. That war took it to Cuba, Puerto Rico, and the Philippines, where its men installed and operated land lines and submarine cable. WORLD WAR I. In that war the Signal Corps greatly expanded its services to the Army, providing telephone, telegraph, radio, and pigeon communications. It also set up photographic and meteorological services, and took its first steps in enemy intercept and direction finding (then called goniometry). Besides laying many thousands of miles of field wire (Signal Corps outpost companies installed and operated the equipment up to the front lines), the Corps literally crisscrossed all France with fixed installations, building 1,724 miles of permanent pole line. By November 1918 it was operating 273 telephone exchanges (which grew to 328 by February 1919) and 144 telegraph offices. From the latter part of 1917 to 1 January 1919, the system handled a total of 7,601,500 telegrams, 870,000 long-distance telephone calls, and 25,184,500 local calls. DEVELOPMENT OF RADIO AND RADAR. The first experimental radio transmission by the Corps over appreciable distances began in 1899. At its laboratories at Ft. Monmouth, N. J. and at Dayton, Ohio, the Corps during the 1930's developed Army radar types and made a beginning with aircraft radio and navigational equipment and with FM vehicular (tank) radios of the SCR-500 and -600 types. All these developments greatly expanded after Pearl Harbor. THE ARMY'S RADIO NETWORK. The development of the worldwide radio network which the Army uses today began with the War Department Radio Net, which the Signal Corps set up in 1921. It handled 3,800,000 words in that first year, and 26,500,000 by 1933. The net expanded enormously in the 1940's, when its title was changed to Army Command and Administrative Network (ACAN). In 1941, ACAN included Seattle (serving the Alaska Communications System) and oversea Army stations at San Juan, Puerto Rico, in Panama, and at Honolulu and Manila, and was handling half a million words a day. By 1945 the ACAN stations encompassed the world, and had a capacity of up to 100,000,000 words a day. During and after World War II, military wire and radio communications were integrated. Carrier systems multiplied the capacity of wire and radio circuits. In the course of World War II the Signal Corps made increasing use of radio teletype and radio relay; the latter, rather than wire, proved at times to be the mainstay of Army communications. (This was increasingly true, a few years later, in Korea.) SUPPLY IN WORLD WAR II. In the six calendar years 1940-45 inclusive the Signal Corps procured for the Army some seventeen billion dollars' worth of equipment and supplies. The following summary table shows the total numbers of various major categories of equipment procured in that period (except that, for a few items, data are incomplete, or exclude part of the sixyear period, etc.). Although the basic duty of the Signal Corps is to provide military communications, it has traditionally taken on many additional allied technical duties for the Army. One example is military photography. The Army's pictorial records of all conflicts since the Spanish-American War have been made by Signal Corps photographers. The Signal Corps Pictorial Center, in its studios at Astoria, Long Island, N. Y., produced 2,650 motion pictures and 1,458 film strips for training purposes between 9 March 1942 and 31 July 1945. These were distributed by the Army Pictorial Service, and were a vital aid in the training of troops. The Pictorial Service also handled photomail and V-Mail letters, photographing about a billion and a quarter of the latter between June 1942 and August 1945. Military aviation in the United States had its genesis in the Aeronautical Section of the Signal Corps which was established on 1 August 1907. It remained under Corps control until May 1918, when the Army established a separate Air Corps. The first flight of an airplane (piloted by O. Wright) on a military installation occurred on 3 September 1908, at Ft. Myer, Va. Following its crash on 17 September, fatally injuring Lt. T. E. Selfridge, on duty with the Signal Corps for aviation service (the first man ever killed in heavier-thanair powered flight), the Wrights pre |