Specially designed to speed the loading and unloading of building materials, prototypes for the WalthersMainline 72' Centerbeam Flatcar have been favorites with shippers since the 1980s. The car's distinctive center partition adds stability to loads and was made in two versions, some with oval cutouts (called "opera windows") and "standard" construction of steel beams and rigging. The WalthersMainline model accurately matches the dimensions and look of its lumber hauling prototype. The HO car is also available in "opera window" and "standard" versions, as appropriate for each roadname.