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-14576
MSRP, Section M, LOCOMOTIVES AND LOCOMOTIVE INTERCHANGE EQUIPMENT: Standard S-5018 – DYNAMIC BRAKING CONTROL
Issued: May 16, 2025
Effective: May 16, 2025
On April 8, 2025, Circular Letter C-14532 was issued to solicit comments on the proposed revisions to update four (4) of six (6) braking curve graphs and eliminate the remaining two (2) obsolete graphs. No comments were received. The revised S-5018 is hereby implemented and effective immediately. A copy is attached to the circular.
The revised S-5018 will be reflected in the next issue of Section M. In the interim, please insert this circular into your copy of MSRP Section M and be governed accordingly.
Call for Comment
C-14563
Revisions to Car Repair Billing Procedures Manual, Errors Codes 8S & 8U, Appendix Y
Issued: May 6, 2025
Effective: 30 days for comment.
IMPORTANT NOTE: It is recommended that this information be shared with all Car Repair Billing and IT personnel in your company that work with or are responsible for car repair invoices submitted to and/or received from Railinc’s Car Repair Billing Data Exchange.
At the March 2025 meeting of the Car Repair Billing Committee, the committee advanced two initiatives to update the CRB Procedures Manual:
- Move error codes 8S & 8U into mandatory rejects by rolling them into Error Codes 8P & 8R effective January 1, 2026 (previously planned to become mandatory rejects effective July 1, 2025)
- Remove one example of an exception that is not valid from the CRB Procedures Manual effective July 1, 2025 to coincide with a deadline already present in Field Manual Rule 4.B.12-4.B.14.
C-14565
CRB Paperless Billing Exceptions Implementation Timeline Revision, Revisions to Office Manual Rule 112 & CRB Procedures Manual, Record Format Type 3 Revision
Issued: May 15, 2025
Effective: 30 days for comment.
IMPORTANT NOTE: It is recommended that this information be shared with all Car Repair Billing and IT personnel in your company that work with or are responsible for car repair invoices submitted to and/or received from Railinc’s Car Repair Billing Data Exchange.
This Circular Letter supplements and supersedes the following AAR Circular Letters:
- C-14261 issued on November 6, 2023
- C-14395 issued on July 1, 2024
At the April 2025 meeting of the Arbitration and Rules Committee, the committee approved a proposal advanced by the Car Repair Billing Committee to incorporate Counter Billing Authority (CBA) into the paperless billing exceptions process. In order to allow time for development of the inclusion of CBAs, the committee also approved a revised implementation timeline for mandatory paperless billing exceptions forward to January 1, 2026.
See circular for full updated timeline and applicable office manual revisions.
C-14578
Revisions to MSRP Section S-II, TRUCK DETAILS AND CASTING CODES, Standard S-378, Side Frame, Cast Steel–Making and Mating, regarding button casting and removal
Issued: May 29, 2025
Effective: 30 days for comment.
The Coupling System and Truck Castings Committee is proposing to modify the button size and removal requirements. Cast buttons must be a minimum of 3/16 inch in height. Removed buttons must be flush to no taller than 1/16 inch and remaining buttons must be sequential.
Proposed updates are highlighted with change bars in the attached file, which will replace S-378 in its entirety when implemented.
Notice of Circulars
C-14564
Soliciting Participants for Inclusion in the 2026 CRB Survey Process
Issued: May 12, 2025
Effective: May 12, 2025
As detailed in C-13558, issued on April 30, 2020, the CRB survey process and calculation methodology now includes these parties in addition to Class I Railroads. In order for new participants’ data to be included in the CRB labor and material calculations for 2026, each of the three individual surveys must be completed and submitted to the AAR by the deadlines identified below:
- Base Wage Rate Survey – submitted to AAR by July 31, 2025
- Overhead Study Survey – submitted to AAR by September 8, 2025
- Material Price Survey – submitted to AAR by November 10, 2025
The deadline for notifying the AAR of your company’s intention to participate is June 15, 2025.
C-14577
Revisions to Field Manual Rule 16
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the Coupling System and Truck Castings Committee to revise Field Manual Rule 16, was reviewed and approved. The entire text of the revision is attached to the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14575
Revisions to Office Manual Rule 122.C
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal to revise Office Manual Rule 122.C, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Office Manual.
C-14574
Revisions to Office Manual Rule 121, Arbitration and Rules Committee Structure
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal to revise Office Manual Rule 121, to revise the membership makeup of the Arbitration and Rules Committee, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Office Manual.
C-14573
Revisions to Field Manual Rules 47 and 48, MD-500
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the Coupling System and Truck Castings Committee to revise Field Manual Rules 47 and 48, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14572
Revisions to Field Manual Rule 41
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the WABL Committee to revise Field Manual Rule 41.B, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14571
Revisions to Field Manual Rule 37, Obsolete
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the WABL Committee to revise Field Manual Rule 37, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14570
Revisions to Field Manual Rule 17.B, Correct Repair Chart
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the Coupling System and Truck Castings Committee to revise Field Manual Rule 17.B, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14569
Revisions to Field Manual Rules 15, 17 and 18, Identification and handling of cracks and hot tears
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the Coupling System and Truck Castings Committee to revise Field Manual Rules 15, 17 and 18, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14568
Revisions to Field Manual Rules 15-18, MD reporting
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advance by the Coupling System and Truck Castings Committee to revise Field Manual Rules 15-18, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14567
Revisions to Field Manual Rule 4.E.17
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advanced by the Car Repair Billing Committee to revise Field Manual Rule 4.E.17, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
C-14566
Revisions to Field Manual Rule 3.E
Issued: May 16, 2025
Effective: July 1, 2025
At the April 2025 meeting of the Arbitration and Rules Committee, a proposal as advanced by the Car Repair Billing Committee to revise Field Manual Rule 3.E, was reviewed and approved. The entire text of the revision is identified in the circular. These changes will be included in the July 1, 2025 updates to the Field Manual.
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Greenbrier’s Regulatory Services Group
Peace of mind for your business.
The Regulatory Management Group, led by James Rader, provides regulatory, engineering, process consulting and advocacy support to the railcar repair industry and the petrochemical rail shipper community.
- ASNT Level III Subscription Services
- DOT Compliance Assessments (Corporate and Plant)
- DOT Hazardous Materials Training (Corporate and Plant)
- Expert Witness Services in Rail-Related Litigation
- Federal Government Claims Mitigation (e.g. FRA and PHMSA)
- Nondestructive Testing Programs
- Quality Assurance Program Development
- Regulatory Counsel and Policy Advocacy
- Railcar Repair Management (Design Review, Drawings, Engineering and AAR Approval Administration)
- Tank Car Reliability and Maintenance Programs (49 CFR Subpart F of Part 180)
- Tank Car Maintenance Data Collection and Reliability Performance Analysis
- Welding Program Development
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.