One really good source of mid-19th century data are the Pennsylvania Canal
Commissioner reports. They are microfilmed and are available at/from the
Pennsylvania State Library (Harrisburg).  I've also  used other
mixed-venture enterprise improvement project reports (mostly canals) which
provide good transportation cost data.  Another one that immediately comes
to mind are the records of the Monongahela Navigation Company (PA-WV), also
reported in:

U.S. Congress.  House
1895 Testimony Relative to Value of Improvements of Monongahela Navigation
Company of Monongahela River, Pennsylvania, and to Commercial Importance of
Free Navigation on Said River. H.Doc. 78. 54th Cong. 1st sess.

1903 Pennsylvania Locks and Dams Nos. 1,3,4, and 5, Monongahela River.
H.Doc. 209. 58th Cong. 2d sess.

1913 Locks Nos. 4 and 6, Monongahela River, Pa. H.Doc. 1217. 62d Cong. 3d
sess.

If I recall correctly, these are available at/from the Historical Society of
Western Pennsylvania (Pittsburgh).  You might also check the US annual
reports on Internal Commerce (these cover a later period, though), as well
as:

United States.  Department of the Treasury
1864 Statistics of the Foreign and Domestic Commerce of the United States.
Government Printing Office, Washington, D.C.

New York.  State Assembly
1879-1880 Proceedings of the Special Committee Appointed to Investigate
Alleged Abuses in the Management of Railroads Chartered by the State of New
York. Eight Volumes.

And,

Hunt's Merhcant's Magazine
1845 Main Line of State Works of Pennsylvania. Hunt's Merchant's Magazine
13:97-151. (Hunts is a really good source for economic data, frequently
reported in tabular formats)

Johnson, E.
1922 History of Domestic and Foreign Commerce of the United States. 1964. B.
Franklin, New York. (good sources cited)

Fishlow, A.
1965 American Railroads and the Transformation of the Antebellum Economy.
Harvard University Press, Cambridge. (good sources cited)

DSR.
________________________________________________
David S. Rotenstein, Ph.D., RPA
Consulting Historian
Columbia, SC 29201
E-mail: [log in to unmask]
Website: http://davidsr01.home.mindspring.com
Phone: (803) 376-1442
________________________________________________