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-14306
Implementation of Revision to AAR MSRP Section J, Specification for Quality Assurance M-1003
Issued: February 1, 2024
Effective: August 1, 2024
The AAR Quality Assurance Committee (QAC) is pleased to announce a new edition of the Manual of Standards and Recommended Practices (MSRP) Section J, Specification for Quality Assurance M-1003. The previous printing was issued January 2022.
The revised MSRP Section J is now available and can be purchased in hard copy or electronic PDF format:
Section J – Quality Assurance M-1003 (2024) – Product Code M1401
The manual can be purchased online at www.aarpublications.com
C-14308
Implementation Effective Immediately: REVISION to Office Manual, Rules 103 and 107, Rack Only Incidents
Issued: February 5, 2024
Effective: February 5, 2024
After publishing the January 2024 Office Manual, it was brought to our attention that the new guidance for “rack only incidents” unintentionally prohibited the billing of destroyed racks. In January 2024, the AAR Car Repair Billing committee met and voted to rescind the Office Manual edits to Rules 103 & 107 disclosed in AAR Circular Letter C-14255. Changes included in this circular.
CPC-1420
Implementation of Proposed Changes to MSRP Section C-III, Specification for Tank Cars (M-1002), Chapter 1, Appendices B, E, R, V, and W
Issued: February 12, 2024
Effective: February 12, 2024
The Tank Car Committee (TCC) has Implementation of Proposed Changes to MSRP Section C-III, Specification for Tank Cars (M-1002), Chapter 1, Appendices B, E, R, V, and W. Implementation of proposals found in CPC-1415, CPC-1416, CPC-1417.
Implementation Summary:
- Updated definitions included in Chapter 1
- Addition of Appendix V, Volume Determination of Tank Car Tanks and Capacity Tables
- Changes to Appendix W resulting from comments received in response to CPC-1401
- Changes to Appendix E to supports changes to Appendix W
- Addition of Appendix V, Volume Determination of Tank Car Tanks and Capacity Tables
C-14314
IMPLEMENTED. AAR Manual of Standards and Recommended Practices (MSRP). Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9461.V1.0
Issued: February 20, 2024
Effective: February 20, 2024
S-9461.V1.0 contains interoperable requirements for messages that support interaction with the MAIN-CDX system including; Data Transfer Request Message, Data Transfer Response Messages, Data Transfer Notification Message, Data Transfer Notification Response Messages and Payload Structures for MAIN-CDX. This document also includes the behavioral requirements for these messages.
Standard S-9461.V1.0 was Adopted in 2024 and is attached to this circular in PDF format. S-9461.V1.0 will be incorporated into the next issue of the MSRP Section K-V Electronics Environmental Requirements and Systems Management.
C-14313
IMPLEMENTED. AAR Manual of Standards and Recommended Practices (MSRP), Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9414.V1.0
Issued: February 20, 2024
Effective: February 20, 2024
S-9414.V1.0 describes the Service Registry which is used to provide the EMP address for a domestic or foreign service based on a well-known ‘service name’. The Service Registry is not used to obtain the EMP address for an asset (e.g. a locomotive). This document describes the process and messages used for obtaining the EMP address for a foreign service.
Standard S-9414.V1.0 was Adopted in 2024 and is attached to this circular in PDF format. S-9414.V1.0 will be incorporated into the next issue of the MSRP Section K-V Electronics Environmental Requirements and Systems Management.
C-14312
IMPLEMENTED. AAR Manual of Standards and Recommended Practices (MSRP), Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9412.V1.0
Issued: February 20, 2024
Effective: February 20, 2024
S-9412.V1.0 describes the requirements for obtaining certificates, issuing Authentication Tokens, and issuing Access Tokens. This document applies to SMIA-2 and other interoperable back-office services.
Standard S-9412.V1.0 was Adopted in 2024 and is attached to this circular in PDF format. S-9412.V1.0 will be incorporated into the next issue of the MSRP Section K-V Electronics Environmental Requirements and Systems Management.
C-14311
IMPLEMENTED. AAR Manual of Standards and Recommended Practices (MSRP), Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9411.V1.0
Issued: February 20, 2024
Effective: February 20, 2024
S-9411.V1.0 describes SMIA-2 architecture, principles and common requirements SMIA-2 provides end-to-end identity assurance by extending the existing ISMP protocol. The scope of SMIA-2 is interoperable systems management messaging; that is, back office to back office system management request between partner roads.
Standard S-9411.V1.0 was adopted in 2024 and is attached to this circular in PDF format. S-9411.V1.0 will be incorporated into the next issue of the MSRP Section K-V Electronics Environmental Requirements and Systems Management.
C-14310
IMPLEMENTED. AAR Manual of Standards and Recommended Practices (MSRP), Section K-V Electronics Environmental Requirements and Systems Management, Standard S-9410.V1.0
Issued: February 20, 2024
Effective: February 20, 2024
S-9410.V1.0 describes the messages used for subscribing to event and status updates for a foreign asset from that roads Event and Status Service. The Interoperable Event and Status service supports the following:
- Interoperable Subscribe Event
- Interoperable Subscribe Status
- Interoperable Get Status
Standard S-9410.V1.0 was adopted in 2024 and is attached to this circular in PDF format. S-9410.V1.0 will be incorporated into the next issue of the MSRP Section K-V Electronics Environmental Requirements and Systems Management.
C-14317
Implementation of Revisions to MSRP Section E, BRAKES AND BRAKE EQUIPMENT, Standard S-475, Hand Brakes, Editorial Corrections to Dimensions
Issued: February 29, 2024
Effective: February 29, 2024
The purpose of this circular letter is to notify the industry of revisions to Section E, BRAKES AND BRAKE EQUIPMENT, S-475, Hand Brakes. Revisions are corrections to the dimensions of the table in 1.3.9.1 and Figure 4.1.
The revised standard S-475 is attached to this circular.
C-14318
Implementation of Revisions to MSRP E BRAKES AND BRAKE EQUIPMENT, S-4032, Trainline Arrangement For Cars With E/F-Type Couplers And Draft System Buff Travel Of 6 To 10 Inches
Issued: February 29, 2024
Effective: February 29, 2024
The purpose of this circular letter is to notify the industry of revisions to Section E BRAKES AND BRAKE EQUIPMENT, with the addition of new S-4032, Trainline Arrangement For Cars With E/F-Type Couplers And Draft System Buff Travel Of 6 To 10 Inches.
The new standard S-4032 is attached to this circular.
C-14319
Implementation of Revisions to MSRP Section E BRAKES AND BRAKE EQUIPMENT, New Standard S-4031, Trainline Arrangement For Cars With E-Type Couplers And With Draft System Buff Travel Of 6 To 10 Inches
Issued: February 29, 2024
Effective: February 29, 2024
The purpose of this circular letter is to notify the industry of revisions to Section E BRAKES AND BRAKE EQUIPMENT, with the addition of new Standard S-4031 Trainline Arrangement for Cars with E-Type Couplers and Draft System Buff Travel of 6 to 10 inches.
The new standard S-4031 is attached to this circular.
Call for Comment
C-14307
Solicitation of Comments for Revisions to MSRP Section C, CAR CONSTRUCTION FUNDAMENTALS AND DETAILS: Proposed new Standard “S-2057 Draft Arrangements, 24 5/8-in. Pocket” and retirement of existing standards S-239, S-243, and S-245
Issued: February 2, 2024
Effective: 30 days for comment.
The purpose of this circular letter is to solicit comments for revisions proposed to Section C, CAR CONSTRUCTION FUNDAMENTALS AND DETAILS. The AAR Equipment Engineering Committee’s (EEC) intent is to consolidate the following 24 5/8-in. pocket standards into one. The proposal is attached to the circular.
C-14316
Solicitation of Comments for Revisions to MSRP Section C, CAR CONSTRUCTION FUNDAMENTALS AND DETAILS, Standard S-2056, Clearance Plate Diagrams for Interchange Service: Update to Plate K and addition of Plate P
Issued: February 22, 2024
Effective: 30 days for comment.
The purpose of this circular letter is to solicit comments for revisions proposed to Section C, CAR CONSTRUCTION FUNDAMENTALS AND DETAILS, Standard S-2056, Clearance Plate Diagrams for Interchange Service. The AAR Clearance Task Force and the Equipment Engineering Committee have agreed to this update relative to clearances for 20′ 3″ autoracks. The proposal is attached to this circular.
C-14315
Solicitation of Comments for Revisions to MSRP Section B FREIGHT CAR DRAFT COMPONENTS, Specification M-921H, Unit Condition Indicator, Standard EOC and COC Cushioning Devices, addition of requirements for all hydraulic cushioning devices
Issued: February 28, 2024
Effective: 30 days for comment.
The purpose of this circular letter is to solicit comments for revisions proposed to Section B FREIGHT CAR DRAFT COMPONENTS, Specification M-921H, Unit Condition Indicator, Standard EOC and COC Cushioning Devices. Additional requirements for all hydraulic end-of-car (EOC) and center-of-car (COC) devices are being added relative to Marking, Identification Tags, Stamping, and Bar Code Labeling, and port configuration. The proposal is attached to this circular.
Notice of Circulars
C-14309
Registration is Open for NARMO 2024
Issued: February 5, 2024
Effective: February 5, 2024
As previously announced in Circular Letter C-14193, the 38th North American Rail Mechanical Operations (NARMO) Seminar will be held May 6–9, 2024 in Nashville, TN. The AAR is pleased to provide additional details and registration information for our 2024 NARMO Seminar.
Dates: Monday, May 6 through Thursday, May 9, 2024
Location: Sheraton Grand Nashville Downtown
CLICK HERE TO REGISTER FOR NARMO 2024
CPC-1419
Recommended Railroad Operating Practices for Transportation of Hazardous Materials
Issued: February 12, 2024
Effective: February 12, 2024
The AAR’s Hazmat Committee reviewed OT-55-R Section I A. and determined that an edit was required to resolve a discrepancy between the definition of a key train, listed in the USHMI SECTION VII, (2), (C), and this document. The edit will be as follows:
- 20 car loads or intermodal portable loads of any combination of hazardous materials
Upcoming Event
American Short Line and Regional Railroad Association (ASLRRA) 2024 Annual Conference & Exhibition
March 24–26, 2024
Greenbrier is a proud sponsor and exhibitor of the ASLRRA conference. Join us in Kansas City, Missouri!
Awards and Recognition
Norfolk Southern Thoroughbred Sustainability Partner Awards
Ultra-High-Strength Steel Gondola™
As part of a joint initiative, this Ultra-High-Strength Steel Gondola™ earned Norfolk Southern’s Thoroughbred Sustainability Partner Awards for Innovation.
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.