Railroads 1,270 History 426 Finance 156 Description and travel 152 Street-railroads 149 Transportation 104 Canals 97 more ... Underground Railroad 80 African Americans 63 Railroads and state 60 Employees 55 Railroad stations 49 Fugitive slaves 45 Rates 45 Streets 45 Freight 44 Design and construction 43 Antislavery movements 38 Locomotives 38 Coal 37 Early works to 1850 36 Railroad law 35 Electric railroads 31 Management 30 Slavery 30 Surveying 29 Commerce 27 Employment 26 Railroad mortgages 26 Local transit 24 Railroad companies 24 Coal mines and mining 23 Pacific railroads 23 Labor unions 22 Bridges 21 Railroad 21 Abolitionists 20 Histoire 20 Railroad bridges 20 Taxation 20 less ...