In the design of the station much thought was given to the architectural features. Since Greece and Rome have furnished architectural inspiration for so many of the public buildings of Washington, a freely interpreted classic may be considered as the recognized architecture of these structures; and as the new station was to be the monumental gateway to the National Capital, it seemed fitting that the architectural motives should be drawn from the triumphal arches of Rome. They inspired Mr. Burnham to design the Union Station as he did. Construction work was begun in August, 1902, the terminal opened October 27, 1907, and was completed in April, 1908. Some of the elements entering into the design of the terminal were unique. In most cities the probable future growth and nature of the traffic plays an important part in the planning of a passenger terminal. Washington has very little suburban traffic; and as it will never become a commercial center, the question of providing for future growth was of minor importance. The main problem was how to care for and provide against abnormal conditions, which arise at least once every four years. The handling of inauguration crowds had always been a heavy expense to the railroads, because they had to provide such elaborate temporary facilities. On the other hand, to provide adequate permanent facilities meant a large expenditure, with the attendant heavy carrying charges. On account of the dilapidated condition of the passenger facilities owned by the companies, and the urgent need of larger and better terminals, a union terminal seemed to show advantages over the separate stations provided for in the acts of 1901. [Illustration: _Courtesy of Commercial Photo Co._ UNION STATION--CONCOURSE] The layout embraces every feature and facility involved in the construction of a first-class terminal, including a depot building planned and constructed after the most modern lines, and containing every feature for the convenience, comfort, and pleasure of the traveling public; the most complete and up-to-date facilities for conducting the business of a large railroad station; a main power plant for furnishing power of every kind required for the successful operation of the station and yards; a large and completely equipped express terminal for caring for the express business handled by the companies; a modern commodious roundhouse and shop layout for caring for repairs to equipment; the most complete interlocking layout and intercommunication system ever constructed; one of the most complete passenger-equipment yards ever built; and a track system covering yards and main tracks within the passenger-terminal zone aggregating about 60 miles of single track.