During the World War I emergency, American railroads were placed under the control of the United States Railroad Administration to facilitate construction, operation, and maintenance. All new steam locomotives ordered during this period were built to one of twelve standard designs developed by a committee of United States Railroad Administration, railroad, and locomotive-builder representatives. This family of locomotives, ranging from 0-6-0 to 2-8-8-2 in size, incorporated the best proven features of the day and marked the first successful standardization of American motive power. Although the United States Railroad Administration period lasted only three years, locomotives continued to be built around these basic designs for another decade. Atlantic Coast Line Class P-5-A 4-6-2 No. 1504, built in 1919 by American Locomotive Co. Richmond Works, is a Light Pacific, the most common United States Railroad Administration passenger design. It served on the Atlantic Coast Line for over 30 years and has survived in almost original condition.