Railroads 470 History 103 Street-railroads 89 Finance 83 Canals 51 Early works to 1850 27 Underground Railroad 26 more ... Streets 20 Transportation 20 Electric railroads 15 Rates 15 Surveying 15 Coal mines and mining 14 African Americans 13 Description and travel 12 Fugitive slaves 12 Taxation 12 Antislavery movements 11 Freight 11 Design and construction 10 Local transit 10 Street railroads 10 Coal trade 9 Commerce 9 Management 9 Right of way 9 Appropriations and expenditures 8 Coal 8 Location 8 Railroad law 8 Abolitionists 7 Bus lines 7 Railroad stations 7 Cars 6 Costs 6 Histoire 6 Law and legislation 6 Race relations 6 Buildings, structures, etc 5 Historic sites 5 less ...