Fonds consists primarily of technical drawings and photographs related to the construction of locomotives by the Canadian Locomotive Company (CLC), the H.K. Porter Company, and the Davenport Locomotive Company. The Fonds has been arranged into four CLC series and two sous-fonds for Porter and Davenport company records.

The fonds reflects Lehmann’s research on Canadian railway development and its sources of locomotives. He conducted research on companies that built locomotives in Halifax, Saint John, Montreal, Toronto, and Hamilton, but there is also an entire series of research files on the succession of companies in Kingston, including particularly the Canadian Locomotive Company. The fonds is arranged into the following nine series: LEH-1) Articles and Talks (1965-1994); LEH-2) Canadian Locomotive Builders Project (1969-1994) on his book project; LEH-3) Canadian Locomotive Builders (1824-1990) LEH-4) Canadian Railway Shops (1859-1900); LEH-5) Canadian Locomotive Co. (1845-1991); LEH-6) Miscellaneous reference files (1858-1985); LEH-7) Locomotives and Railways, Articles and Books (1876-2000); LEH-8) Photos and Slides (1852-1987); et LEH-9) Additional Material (1884-1999). The last series, LEH-9, includes all the material transferred in the 2023 accrual.