Texas and New Orleans Railroad Company.
Thomas, Cowperthwait & Co.
Thomas, G. F.
Thomson, J. Edgar (John Edgar), 1808-1874.
Through Traffic Railway.
Toledo, Ann Arbor, and Grand Truck Railway.
Toledo, Ann Arbor, and North Michigan Railway Company.
Toledo, Cincinnati, and St. Louis Railroad Company.
Toledo, Peoria & Warsaw Railway.
Toledo, Wabash, and Great Western Railroad.
Trautwine, John C. (John Cresson), 1810-1883.
Tunis, W. E.
Tunison, E. L.
Tyrone and Lock Haven Railroad Company.
Union Pacific Railroad Company.
Union Pacific Railway Company.
United States Coast Survey.
United States. Army. Quartermaster Corps.
United States. Congress. House.
United States. Congress. Senate.
United States. Department of Commerce and Labor. Bureau of Statistics.
United States. General Land Office.
United States. Railway Mail Service.
United States. War Department.
Van Cleef, John T.
Vaughan, David, active 1849-1864.
Virginia Central Railroad Company.
Virginia, Kentucky, and Ohio Railroad.
Virginia, Tennessee, and Georgia Air Line Railroad.
Virginia. Board of Public Works.
W. Endicott & Co.
Walker, Evans & Co.
Walker, Evans & Cogswell.
Wall, J. Sutton.
Walling, Henry Francis, 1825-1888.
Warren, G. K. (Gouverneur Kemble), 1830-1882.
Washington City and Point Lookout Railroad.
Washington and Atlantic Railroad.
Washington and Ohio Railroad Company.
Washington and St. Mary's Railroad.
West Philadelphia Rail Road Company.
West Virginia Midland Railroad.
Westbrook, J. B.
Western Vermont Railroad.
Western and Atlantic Railroad Company.
Wheeling and Cincinnati Mineral Railway.
Whipple, Amiel Weeks, 1817?-1863.
Whitney, Asa, 1797-1872.
Williams Smith, Issac.
Williams, Henry T.
Williams, W. (Wellington)
Williamson, R. S. (Robert Stockton), 1824-1882.
Williamsport and Elmira Railroad Company.
Winchester and Potomac Railroad Company.
Wisconsin Central Railroad Company (1871-1899)
Woodward, Tiernan, and Hale.
Worcester, George P.
Wright, Benjamin, 1770-1842.
Yeager, Joseph, approximately 1792-1859.
Young, J. H. (James Hamilton)
Young, John (Topographical engineer)