232.103—General requirements for all train brake systems.

(f) Each car in a train shall have its air brakes in effective operating condition unless the car is being moved for repairs in accordance with §§ 232.15 and 232.609. The air brakes on a car are not in effective operating condition if its brakes are cut-out or otherwise inoperative or if the piston travel exceeds:
(l) Except as otherwise provided in this part, all equipment used in freight or other non-passenger trains shall, at a minimum, meet the Association of American Railroads (AAR) Standard S-469-47, “Performance Specification for Freight Brakes,” contained in the AAR Manual of Standards and Recommended Practices, Section E (April 1, 1999). The incorporation by reference of this AAR standard was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain a copy of the incorporated document from the Association of American Railroads, 50 F Street, NW, Washington, DC. 20001. You may inspect a copy of the document at the Federal Railroad Administration, Docket Clerk, 1200 New Jersey Avenue, SE., Washington, DC or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
Locomotives PSI
(1) Minimum brake pipe air pressure:
Road Service 90
Switch Service 60
(2) Minimum differential between brake pipe and main reservoir air pressures, with brake valve in running position 15
(3) Safety valve for straight air brake 30-55
(4) Safety valve for LT, ET, No. 8-EL, No. 14 EI, No. 6-DS, No. 6-BL and No. 6-SL equipment 30-68
(5) Safety valve for HSC and No. 24-RL equipment 30-75
(6) Reducing valve for independent or straight air brake 30-50
(7) Self-lapping portion for electro-pneumatic brake (minimum full application pressure) 50
(8) Self-lapping portion for independent air brake (full application pressure) 30-50
(9) Reducing valve for high-speed brake (minimum) 50
[66 FR 4193, Jan. 17, 2001, as amended at 67 FR 17581, Apr. 10, 2002; 73 FR 61553, Oct. 16, 2008; 74 FR 25174, May 27, 2009]