All of the above are 4-3/4" gauge, I ride on the tender, except for the Shay which requires a riding car. Top engine is a Little Engines Pacific, built by a guy in Wisconsin in the 1980's, coal fired. The copper jacketed engine is also a Little Engines Pacific, coal fired, built by a guy in the 1970's in Minnesota. The 2 cylinder Shay is propane fired, scratch built by a friend in Minnesota from plans furnished by a guy in Michigan. The 2-4-4-2 articulated was built by 2 guys in Minnesota who worked on it, from their own plans, starting in 1974, completed in 2010, and is also propane fired. The prototype for this engine is a Baldwin, which was recently restored and runs on the Oregon Coast RR, and goes by the name of "Skookum" (Google it).