There is a piece of legislation in Congress, HR 1806 http://thomas.loc.gov/cgi-bin/bdquery/z?d111:h1806: . The synopsis is that it gives companies a 25% tax credit against freight rail infrastructure investments.

It is a largely bi-partisan bill, sponsored by Congressman Meek - VA (D). Work is being done to get it passed, but if there is enough support, it may be rolled into a larger piece of economic legislation.