49 CFR § 179.20
Service equipment; protection systems
November 18, 2020
If an applicable tank car specification authorizes location of filling or discharge connections in the bottom shell, the connections must be designed, constructed, and protected according to paragraphs E9.00 and E10.00 of the AAR Specifications for Tank Cars (IBR, see §171.7 of this subchapter).
[68 FR 75759, Dec. 31, 2003]