by Bob Krone
Union Pacific 4-6-6-4 puzzle, based on an original photo by Bob Krone (photo copyright Bob Krone -- used with permission). Photographed at Rock Springs, Wyoming, June 29, 1982.
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.