Railroads 488 History 122 Street-railroads 99 Finance 83 Canals 52 Underground Railroad 33 Early works to 1850 27 more ... Transportation 21 Streets 20 Electric railroads 17 Fugitive slaves 17 African Americans 16 Antislavery movements 15 Rates 15 Surveying 15 Coal mines and mining 14 Description and travel 12 Taxation 12 Freight 11 Local transit 11 Abolitionists 10 Design and construction 10 Street railroads 10 Coal trade 9 Commerce 9 Histoire 9 Management 9 Railroad stations 9 Right of way 9 Appropriations and expenditures 8 Coal 8 Location 8 Railroad law 8 Bus lines 7 Cars 7 Historic sites 7 Race relations 7 Buildings, structures, etc 6 Costs 6 Law and legislation 6 less ...