Our Track & infrastructure. Maintenance Equipment ; Railroad Connections Interactive Maps of U.S. Freight Railroads Railroads are the lifeblood for North America's freight transportation. There are seven major railroads in the United States (Class I railroads) and over shortline and regional railroads (Class II & Class III railroads). These lines . The Melbourne to Albury railway originally consisted of separate 1, mm (5 ft 3 in) gauge and 1, mm (4 ft 8 1 ⁄ 2 in) gauge single track lines, but when traffic on the broad gauge declined, the lines were converted to bi-directional double track 1, mm (4 ft 8 1 ⁄ 2 in) gauge lines. Use a red crayon to trace one pair of parallel lines in the trapezoid below. 3. How are the sun's rays like mathematical rays? _____ _____ _____ 4. Color the shapes below that have perpendicular line segments. 5. Are the metal rails that make up train tracks an example of parallel lines, intersecting lines, or perpendicular lines? Explain.