Explanatory notes
… sections most commonly falling in this heading are H, I, T, capital omega, Z and U (including channels), obtuse, acute … heavier angles, shapes and sections (e.g., girders, beams, pillars and joists) are used in the construction of bridges, … : (a) Welded angles, shapes and sections, and sheet piling ( heading 73.01 ), and railway or tramway track …