Central Maine and Quebec Railway B23-7 puzzle, based on an original photo by J.A. Muscarella (photo copyright J.A. Muscarella -- used with permission). Photographed at Brownville Junction, Maine, July 2, 2017.
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.