How many people traveled through Washington D.C . 's Union Station each day during World War II ?
In the 1930s , his sons Thomas F. Gilbane , Jr. and William J. Gilbane , Jr. joined the company and made Gilbane ’s reputation as a pioneer in construction management — first with major defense projects during World War II , and then with the Smithsonian ’s National Air and Space Museum , which opened on time and budget in Washington , D.C. on July 4 , 1976 .