Canals Railroads 75 History 30 Navigation 19 Inland navigation 17 Law and legislation 17 Public works 14 more ... Design and construction 11 Costs 10 Canal companies 9 Finance 9 Rates and tolls 9 Canaux 8 Commerce 7 Early works to 1850 7 Roads 6 Surveying 6 Water-supply 6 Coal trade 5 Corporations 4 Description and travel 4 Locks (Hydraulic engineering) 4 Lotteries 4 Rivers 4 Transportation 4 Appropriations and expenditures 3 Banking law 3 Bridges 3 Directors of corporations 3 Governmental investigations 3 Internal improvements 3 Maintenance and repair 3 Periodicals 3 Railroad law 3 Recreational use 3 Taxation 3 Telegraph 3 Aqueducts 2 Canal construction workers 2 Chesapeake and Ohio Canal 2 less ...