Railroads 80 Street-railroads 68 History 54 Streets 41 Local transit 24 Railroad stations 22 Railroads, Elevated 20 more ... Transportation 16 African Americans 13 Buildings, structures, etc 13 Description and travel 13 Electric railroads 11 Street railroads 11 Subways 10 Bridges 9 Underground Railroad 9 Buildings 8 Architecture 7 Bus lines 7 Cars 7 Crossings 7 Employment 7 Finance 7 Women 7 Civil rights 6 Railroad bridges 6 Railroad employees 6 Trolley cars 6 Design and construction 5 Harbor 5 Law and legislation 5 Public buildings 5 Race relations 5 Transit systems 5 Urban transportation 5 Abolitionists 4 Appropriations and expenditures 4 Commerce 4 Commuters 4 Commuting traffic 4 less ...