About AAR Circular Letters
Circular letter summaries are produced monthly by Greenbrier Management Services Group.
AAR circular letters provide information of general applicability to the railroad industry, including proposed and final rules, revisions, standards and recommended practices, and calls for comments. These summaries provide the main points of circular letters issued in the prior month, as well as important implementation deadlines.
For access to the complete circular letter, please go to my.aar.org/circulars. Circular letters are a fee-based service provided by the AAR’s Transportation Technology Center Incorporated (TTCI). You may subscribe online at publications@aar.com or call 719.584.0538.
Implementation Circulars
C-14613
Subject: Implementation of Revisions to MSRP, Section M, LOCOMOTIVES AND LOCOMOTIVE INTERCHANGE EQUIPMENT: Standard S-5018 – DYNAMIC BRAKING CONTROL
Summary: This circular letter notifies the industry of revisions to the Manual of Standards and Recommended Practices (MSRP) – Section M, specifically Standard S-5018 regarding Dynamic Braking Control. The revised S-5018 is implemented effective immediately and includes a new section on dynamic brake warning criteria, with no comments received on the proposed revisions.
Date: 2025-09-12
Effective Date: 2025-09-12
C-14617
Subject: Implementation of Revisions to MSRP Section I, INTERMODAL EQUIPMENT MANUAL, New RP-856, Multi-Car Power Pack Electrical Cable Tie Down
Summary: This circular letter notifies the industry of revisions to MSRP Section I, INTERMODAL EQUIPMENT MANUAL, introducing new RP-856 which details the recommended practice for power pack generator containers providing electrical power to refrigerated containers on railcars. Comments received on a previous solicitation were considered, resulting in editorial changes and removal of certain sections, and the recommended practice RP-856 is now implemented and effective immediately.
Date: 2025-09-19
Effective Date: 2025-09-19
C-14618
Subject: Implementation of Revisions to MSRP Section AS, ADMINISTRATIVE STANDARDS SUPPLEMENT, Standard S-046 Definitions of Terms for the AAR Manual of Standards and Recommended Practices
Summary: This circular letter notifies the industry of revisions to Section AS, ADMINISTRATIVE STANDARDS SUPPLEMENT, Standard S-046, Definitions of Terms for the AAR Manual of Standards and Recommended Practices. Comments received from a previous solicitation were considered, resulting in changes such as renaming Standard Practice to Standard Procedure and modifying example descriptions.
Date: 2025-09-22
Effective Date: 2025-09-22
C-14619
Subject: IMPLEMENTED, AAR Manual of Standards and Recommended Practices (MSRP) Section K-I Railway Electronics Systems Architecture and Concepts of Operations, Standard S-9070 – Appendix A.V0.0
Summary: S-9070 – Appendix A.V0.0 to ITC Human Machine Interface Standard S-9070.V2.0 defines the human-machine interface standards for the initial version of the OPA software that supports Positive Train Control Office-Locomotive Segment – Interface Control Document (ICD), S-9361.V3.1, which specifies Interface Version 4 (IV4). The update frequency of the AAR document and the content of this appendix are not the same, therefore the information in the appendix is stored separately from the document. Nevertheless, this information shall be considered part of Standard S-9070.
Date: 2025-09-30
Effective Date: 2025-09-30
C-14620
Subject: IMPLEMENTED, AAR Manual of Standards and Recommended Practices (MSRP) Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9416.V1.1
Summary: S-9416.V1.1 describes the minimal set of behaviors that a Client must comply with for interfacing with ITC Systems Management. It also describes behavior requirements for the OPA and FTS client to be compliant with the PSA-2 security architecture, specifically for bandwidth constrained remote applications.
Date: 2025-09-30
Effective Date: 2025-09-30
Call for Comment
C-14612
Subject: Solicitation of Comments for Revisions to AAR MSRP Section J, Specification for Quality Assurance M-1003
Summary: This circular solicits comments for revisions to MSRP Section J, Specification for Quality Assurance M-1003. The draft includes substantial and editorial changes, with a planned release date of February 2026 and a six-month compliance period for facilities.
Date: 2025-09-08
C-14616
Subject: Solicitation of Comments for Revisions to MSRP Section S-III, COUPLER AND YOKE DETAILS, Standards S-108, S-155, and S-165, regarding MSRP references and coupler butt dimensions and tolerances for E68DE, SBE68DE, and SE68DE couplers
Summary: This circular letter solicits comments for revisions proposed to Section S-III, Standards S-108, S-155, and S-165 related to coupler and yoke details. The proposed revisions include improved image quality, added butt dimensions and tolerances, added references to other standards, and a note on dimensions without tolerances to be treated as reference dimensions.
Date: 2025-09-19
Notice of Circulars
C-14609
Subject: Informational Circular, Car Repair Facility Labor Rate – Effective October 1, 2025
Summary: The Car Repair Facility Labor Rate effective October 1, 2025 is $172.27, a decrease of $1.51 (or -0.9%) from the labor rate estimated on July 1, 2025. Wages and weights were re-benchmarked from 2023 to 2024 statistics for the U.S. Class I Railroads, Non-Class Is and Running Repair Agents, with the replacement of 2023 data with 2024 data being the primary driver of the change.
Date: 2025-09-05
Effective Date: 2025-10-01
C-14610
Subject: Informational Circular: Editorial & Reference Additions to MSRP, Section M, LOCOMOTIVES AND LOCOMOTIVE INTERCHANGE EQUIPMENT: Specification M-915 – QUALITY ASSURANCE REQUIREMENTS FOR LOCOMOTIVES AND LOCOMOTIVE COMPONENTS
Summary: This circular advises the industry of editorial and reference updates made to the subject standard. It includes the addition of two Section J Quality Assurance Specification activity codes B13 and B17 under technical approval requirements and clarifies harmonization of Section M requirements with locomotive activity codes in MSRP Section J.
Date: 2025-09-08
Effective Date: 2025-09-08
C-14611
Subject: Registration is Now Open for February 2026 AAR Quality Assurance Industry Conference
Summary: The Association of American Railroads (AAR) Quality Assurance Committee (QAC) announces that registration is open for the 38th Annual AAR Quality Assurance Industry Conference, scheduled for February 17-19, 2026, in St. Petersburg, Florida. The conference will cover topics such as audit consistency, auditing practices, M-1003 Quality Assurance Specification changes, and will feature industry training presentations and workshops.
Date: 2025-09-08
Effective Date: 2025-09-08
C-14614
Subject: Informational Circular, Canadian Car Repair Facility Labor Rate – Effective October 1, 2025
Summary: The Canadian Car Repair Billing Labor Rate calculation for October 1, 2025 is $257.06 CAD, which is an increase from the previous calculation for July 1. The currency conversion factors and wage rebenchmarking from 2023 to 2024 wage statistics were used to determine this increase. The change will be reflected in the October 1, 2025 release of the Canadian Price Master.
Date: 2025-09-12
Effective Date: 2025-10-01
C-14615
Subject: Informational Circular, System Integration Testing Open for CRB Paperless Billing Exceptions Process, Office Manual Rule 112.H.4 & CRB Procedures Manual
Summary: This AAR Circular Letter supplements three prior letters outlining changes to Office Manual Rule 112.H.4 and the CRB Procedures Manual related to the incorporation of paperless billing exceptions into the CRBDX process scheduled for implementation on January 1, 2026. System integration testing is now available for all CRBDX participants, and submission and receipt of paperless billing exceptions are scheduled to go live effective Monday, January 5, 2026.
Date: 2025-09-18
Effective Date: 2025-09-18
AAR Hazmat & Tank Car Committee meetings
October 13–16, 2025 | Addison, TX
The Greenbrier Companies is a proud exhibitor and sponsor.
Greenbrier’s Regulatory Services Group
Peace of mind for your business.
Led by Diana Aylward, Greenbrier’s Regulatory Management Group provides regulatory, engineering, process consulting and advocacy support to the railcar repair industry and the petrochemical rail shipper community.
Our core services include:
- DOT Compliance Assessments (Corporate and Plant)
- DOT Hazardous Materials Training (Corporate and Plant)
- Federal Claims Mitigation Support (e.g., FRA and PHMSA)
- Regulatory Counsel and Policy Advocacy
- Railcar Repair Management (Design Review, Drawings, Engineering and AAR Approval Administration)
- Tank Car Reliability & Maintenance Programs (per 49 CFR Subpart F of Part 180)
- Tank Car Maintenance Data Collection & Performance Analysis
For inquiries about these summaries or any of our services, please reach out to: regulatoryservices@gbrx.com
About Greenbrier Management Services (GMS)
Greenbrier Management Services (GMS) is North America’s most comprehensive railcar management solutions provider. GMS manages nearly 400,000 railcars and has invested over 20 years in developing technology, processes, and people to provide the best railcar management products and services in the industry. GMS is powered by proprietary software and the best subject matter experts in the railcar business.
COMPREHENSIVE. INTEGRATED. VALUE.
Combined, these two vitally important capabilities are able to deliver world-class solutions to every type of customer, from Class I railroads, lessors and industrial shippers to financial investors. GMS brings broad expertise to cover nearly any railcar management need that customers may have and its integrated solutions and reporting can be customized for any customer function or management need.