The Commonwealth Railway System is the HO scale model railroad layout of the Pepperell Siding Model Railroad Club and features a multi-level dual mainline track permanent layout on the second floor. The club has a meeting room, fully equipped workshop, and module storage space on the first floor. The club also has 55 (2,4,6, and 8 foot long) modules which are set up at four MA and NH model railroad shows each year. The club has removed a 38-foot-long section of its permanent layout to replace the modules with a three-level single track permanent layout to better support the club’s monthly operating sessions.