Railroads 29 Transportation 25 History 22 Canals 6 Finance 6 Bus lines 4 Coal 4 more ... Excavations (Archaeology) 4 Local transit 4 Mergers 4 Antiquities 3 Canal companies 3 Coal mines and mining--Pennsylvania 3 Emigration and immigration 3 Histoire 3 Jews 3 Local officials and employees 3 Local transit--Pennsylvania--Philadelphia 3 Philadelphia (Pa.)--Politics and government--20th century 3 Taverns (Inns) 3 World War, 1939-1945 3 Affirmative action programs--Government policy--United States--History--20th century 2 Banks and banking--Pennsylvania 2 Bridges 2 Business and manufacturing--Pennsylvania--Philadelphia--20th century 2 Centennial Exhibition (1876 : Philadelphia, Pa.) 2 Charities--Pennsylvania--Philadelphia 2 Circus 2 Coaching (Transportation) 2 Coal Industry--20th century 2 Colonization 2 Commerce 2 Consumer activism--20th century 2 Description and travel 2 Economic conditions 2 Erlebnisbericht 2 Ethnic relations 2 Exhibitions 2 Historic bridges 2 Inland water transportation 2 less ...