HO Code 100 with black ties and nickel silver rail. Precisely engineered angles of intersection to solve most crossing requirements. For double crossovers use the 19 degree crossing with #6 turnouts. The 19 degree crossings are especially suited for junctions between double-track mainlines.
Precisely engineered with black injection molded plastic and featuring black ties and nickel silver rail, Code 100 is extremely popular and considered an industry standard.