History 24 Street-railroads 21 Railroads 20 Streets 13 Description and travel 12 Buildings, structures, etc 9 Transit systems 8 more ... Social life and customs 6 Bus lines 5 Commerce 5 Transportation 5 Buildings 4 Electric railroads 4 Underground Railroad 4 African Americans 3 Appropriations and expenditures 3 Architecture 3 Cars 3 Coal trade 3 Finance 3 Histoire 3 Local transit 3 Railroad stations 3 Suburbs 3 Subways 3 Buildings and structures 2 Central business districts 2 Commuting traffic 2 Directories 2 Harbor 2 Railroads, Elevated 2 Slaughtering and slaughter-houses 2 Watercolor painting 2 Abolitionists 1 Abolitionnistes 1 Abolitionnistes noirs américains 1 African American abolitionists 1 African American women 1 Airlines 1 Antislavery movements 1 less ...