by Chris Mohs
Southern Pacific Railroad ML 4000 CC puzzle, based on an original photo by Chris Mohs (photo copyright Chris Mohs -- used with permission). Photographed at Niles Canyon, California, July 20, 2019.
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.