Lombard seam log hauler links:

Video of Lombard steam log hauler “Nina” operating in 1912:

Video of Lombard steam log hauler at Cunliffe Depot operating in 1932

History of Crawler Tractors
https://www.youtube.com/watch?v=U1ZlnE200msHIstory of Crawler Tractors

Lombard steam log hauler operating manual and parts diagrams:
http://umaine.edu/met/files/2013/01/Lombard-List-of-Parts.pdf

American Society Mechanical Engineers paper “The Log Haulers” by Lore Rogers and Caleb Scribner:
https://www.asme.org/getmedia/20522eb3-38e9-4bd0-b4da-c33e89e21b77/79-Lombard-Steam-Log-Hauler-1910.aspx

Lombard development history by Terry Harper:
http://forums.justoldtrucks.com/21256/Lombard

Final restoration work on Lombard 38 at Maine Forest and Logging Museum:

2014 – Lombard Steam Log Hauler Restoration

Early restoration work on Lombard 38, including casting and building new steam engines:
http://www.umit.maine.edu/~herbert.crosby/lombard2/

Videos of Lombard 74 operating in winter 2000 towing log sleds:

http://bp-manager.ume.maine.edu/viewResource.html?guid=945D0FE60536C44455882A87EA0F153F

Video of steam and gas Lombard log haulers at Cunliffe Depot on the Allagash Wilderness Waterway:

Video of Lombard 39 at the Ashland Logging Museum:

Video of Loek Prop’s working live steam Lombard steam log hauler model:

Video of Lombard 100th Anniversary Celebration at Maine Forest and Logging Museum:

Loek Prop’s Lombard steam log hauler website:
http://www.depuffendeschoorsteen.com/construction-log-hauler-3-/

Lombard #38 arriving at Maine Forest and Logging Museum in 1990: