On August 27, 1940, as World War II engulfed both Europe and the Orient, a joint resolution of the United States Congress authorized President Franklin D. Roosevelt to federalize the National Guard. Within days, Roosevelt issued orders for the mobilization of several state National Guard units. The Texas National Guard began its tour of duty as the Thirty-sixth Infantry Division, United States Army, by reporting for federal active duty to Camp Bowie, near Brownwood, in the autumn of 1940. Within weeks, the new division increased its manpower from 11,737 officers and men to nearly 15,800 by the addition of new officers and Selective Service inductees from Texas and the surrounding states. The division participated in maneuvers in Louisiana during the summer of 1941. After the Thirty-sixth returned from the war games, the army alerted the Second Battalion, 131st Field Artillery, for assignment. On the evening of November 10, 1941, the battalion entrained at Camp Bowie en route to the West Coast; eleven days later the unit boarded the United States army transport Republic at San Francisco and joined a convoy bound for the Philippines.
The Republic was sailing west of Hawaii on December 7, 1941, when the troops learned of the Japanese attack on Pearl Harbor. The convoy, still proceeding toward the Philippine Islands, which were under attack from another Japanese force, received orders to sail to Brisbane, Australia; the ships arrived there on December 22. Six days later, the battalion was ordered to board a Dutch ship, the Bloemfontein, and sail to Surabaya, Java, to provide ground support for an army air force unit. The Texans arrived on January 11, 1942, the same day the Japanese began invading the Dutch islands. Initially, the battalion acted as ground crew for the Nineteenth Heavy Bombardment Group, which had been forced to leave its original support sections at Clark Field when fleeing the Philippines. Shortly, when the bomb group was ordered to Australia, the flyers asked their leaders to allow the Texans to accompany them to Australia, since they were desperately needed. But the Second Battalion was left in Java to support the morale of the people there. The unit earned the title of "Lost Battalion" because they were not evacuated with other military forces. The Dutch surrendered the islands on March 8, 1942.
The Japanese imprisoned the Texans, along with 5,500 British and Australian troops, at a camp called TanJong Priok, near Batavia. Five weeks later the battalion marched to a new prison known as Bicycle Camp, where they encountered the first of many acts of Japanese brutality. On October 2, 1942, nearly 200 battalion members were marched on board ship and transferred to Singapore. Nine days later most of the remaining members followed, and the group was reunited at Changi Barracks POW camp, formerly a British army post, before being shipped to Moulmein, Burma, on January 11, 1943. The Texans traveled by train to Thanbyuzayat, Burma, and immediately began work on the Japanese "Railroad of Death," which ultimately connected Burma to Bangkok, Siam. The unit labored in various work camps on the railroad, including assisting on the famous "Bridge over the River Kwai," and suffered numerous casualties and deaths. Seventy thousand Allied prisoners of all nationalities perished on the project. In 1944 the Japanese transferred some of the Texans to prison camps in Cambodia and Vietnam and others to Bangkok, where the survivors of the Second Battalion remained for the rest of the war.