by Dave Schauer
Canadian National Railway SD70M-2 puzzle, based on an original photo by Dave Schauer (photo copyright Dave Schauer -- used with permission). Photographed at Green Bay, Wisconsin, July, 2015.
The "Easy" version of the puzzle has about 100 pieces, "Medium" has about 200 pieces, "Hard" is about 300 pieces. For the Online puzzles, see the Online Puzzle Tips.