Summary of AAR Specifications
Norfolk Southern Intermodal Rules Circular #2 is the governing document related to equipment requirements.
- Section 2.5 “Governing Publications” specifically AAR M-931 Trailers for Intermodal Service defines the design requirements for highway trailers intended for railroad intermodal service.
- Section 4.2 “Equipment Specifications” describes the basic requirements for equipment shipped via rail
A few highlights:
- Lift Pads (Bottom Rail Protectors) installed on the bottom rail and cross members per AAR M-931, Sections 4.4 through 4.4.4.
- Top Rail Protectors installed on the top rail per AAR M-931, Sections 4.5 through 4.5.3
- Kingpin must meet requirements of M931, Section 4.2.3.1, the distance from the center of the kingpin to the foremost front of the trailers should be 36” and any deviation must be identified.
- Rear doors locking devices shall preclude undesired unlatching as defined in AAR M-931, Appendix C, 7.5.
- Air Ride Suspension should have stops or other means to prevent over extension which could cause damage to airbags during lift on/off operations.
- Nose mounted refrigeration unit should be fitted with a protective cage or other means to prevent damage caused by loading/unloading operations due to close clearances with adjacent trailers.