Walthers Cornerstone Series Kit HO Scale Machine Shop From the Manufacturer While most roads had one major backshop, making repairs at outlying terminals was soon shown to be faster and more cost-effective. As new engine terminals were built, most received a machine shop capable of handling just about any type of repair that might be needed. This all-new kit matches the design of the Modern Roundhouse (933-2900, sold separately), and can be built as an attached or freestanding building. It also includes a boiler house, which would supply steam, electricity and compressed air to the entire facility. Large roll-up doors can be built open or closed, and the baseplate has slots that accept popular rail sizes.