I designed and built this engine to replace the single acting Mamod one on Traction engine and steam rollers.
It puts the cylinder inboard in a more realist position.
I don't have a Mamod engine but am now building my own version as the engine runs so well.
Big thanks to Retro SteamTech channel for giving me some dimentions of a Mamod roller.
Check out Allan's Roller restoration here:    • Mamod SR1 Steam Roller