Other
Early works to 1850
Railroads
Canals
7
Commerce
3
Location
3
Surveying
3
Transportation
2
Appropriations and expenditures
1
Coal
1
Coal trade
1
Congresses
1
Estimates
1
Governmental investigations
1
History
1
Internal improvements
1
Locomotives
1
Lotteries
1
Management
1
Pennsylvania imprints
1
Pennsylvania railroad
1
Philadelphia and Erie railroad
1
Railroad
1
Railroad companies
1
Rates and tolls
1
Stock companies
1
Welsh, Henry
1