Section 174.201 - Class 2 (gases) material cylinders(a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2 (gases) materials being transported in a rail car must be: (1) Securely lashed in an upright position so as to prevent their overturning;(2) Loaded into racks securely attached to the car;(3) Packed in boxes or crates of such dimensions as to prevent their overturning; or(4) Loaded in a horizontal position.(b) Specification DOT-4L (§ 178.57 of this subchapter) cylinders being transported in a rail car must be loaded in an upright position and be securely braced.(c) Cylinders containing Class 2 (gases) materials may be transported in stock cars, gondola cars and flat cars. However, they may not be transported in hopper bottom cars.Amdt. 174-26, 41 FR 16092, Apr. 15, 1976, as amended by Amdt. 174-26A, 41 FR 40685, Sept. 20, 1976; Amdt. 174-32, 43 FR 48644, Oct. 19, 1978; Amdt. 174-68, 55 FR 52682, Dec. 21, 1990