Detail for Crossings on Curves This Blair Line HO Scale Curved Wood Grade Crossing is ready to install on your highway and road crossings. Similar to those found all over North America, laser-cut wood kits are detailed with laser-etched boards and bolt holes. Curved Wood Grade Crossings are available in a variety of radii to fit common layout curved track. Curved crossings will fit curves plus or minus 1′ of listed radius. See the entire line of Blair Line HO Scale wood grade crossings.