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Subpart A—Introduction, Approvals and Reports8

Subpart B—General Design Requirements11

Subpart C—Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120)31

Subpart D—Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW, 115AW, and 117AW)69

Subpart E—Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW)20

Subpart F—Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A)44

Regulationcurrent

49 CFR 179.400-11

-11 Welding.

Current as of 2026-08-18 Government source

eCFR editorial compilationAuthoritative but unofficial

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(a)Except for closure of openings and a maximum of two circumferential closing joints in the cylindrical portion of the outer jacket, each joint of an inner tank and the outer jacket must be a fusion double welded butt joint.#

(b)The closure for openings and the circumferential closing joints in the cylindrical portion of the outer jacket, including head to shell joints, may be a single welded butt joint using a backing strip on the inside of the joint.#

(c)Each joint must be welded in accordance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter).#

(d)Each welding procedure, welder, and fabricator must be approved.#