Machine Shop Kit HO ScaleWalthers Cornerstone Machine Shop Kit HO Scale Walthers Cornerstone #: 933 2902 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 kit matches the design of the Modern Roundhouse (933 2900, sold separately), and can be built as an