AAR Rules

Dennis Storzek <dennis@...>


I occasionally browse the Modern Freight Cars List, and noticed this posting last night, which I've re-posted here with Mr. Dawson's permission. Mr. Dawson was nice enough to add a little biographical information, which I've added at the bottom.

AAR Rules

I suspect that many, probably most, members of the railroad historical and enthusiast communities do not fully appreciate the significance and power of the AAR Interchange Rules.  How many industries can one think of in which your competitor can inspect your capital equipment, decide based on his inspection that it needs to be repaired, perform the repairs, send you a bill for the repairs (the arrival of which is likely the first that you have heard of it), and you are obligated to pay the bill?  Railroad freight cars do operate under such a system.  The origins of the freight car interchange system and of the railroad associations that control it are described in John H. White’s magnificent book, The American Railroad Freight Car.  To ensure that freight cars running on lines other than those of the car owner can operate safely and be repaired with a minimum of disruption and delay, all parties that operate cars in interchange, that is to say on lines other than their own, agree to subscribe to and be governed by the AAR Interchange Rules.  The rules are enforced by the fact that any railroad can refuse to accept cars offered in interchange that do not comply with the Interchange Rules.  Note that this does not prevent railroads from operating non-compliant cars on their own lines, although such cars are still subject to the requirements of the FRA Freight Car Safety Standards and safety appliance regulations.  It also does not prevent individual railroads from operating non-compliant cars by agreement among themselves.  For example, the 125-ton trucks used on most articulated double stack cars are not authorized for unrestricted interchange, but most railroads accept them over particular lines that can handle the higher axle loadings.  And the AAR does have standards for the wheels, axles, and bearings used on those cars. 


The Interchange Rules serve several different functions: 


  1. They ensure that the components of one car operate in harmony with those of other cars in a train.  The couplers on adjacent cars must couple and uncouple with each other reliably and must be at a known location on the car.  Cars’ air brake systems must respond in a predictable manner to control signals sent from the engineer’s brake valve.  It’s hard to imagine anything more crucial than that the cars in a heavy train descending a steep grade do not run away when the engineer makes a brake application and expects a particular speed to result. 
  2. They ensure that major components are interchangeable regardless of manufacturer, thereby reducing the number of different components that have to be stocked in repair facilities.  Thus, any E60 coupler (and each of its internal components) can be replaced by any other E60 coupler or component.  The ability of a train crew to replace a broken coupler knuckle out on the road is dependent on the knuckle kept in the locomotive (or caboose, in the past) being interchangeable with the one that failed. 
  3. Ensuring that cars in a train and their components have a minimum degree of strength to perform safely in the harsh railroad operating environment.  One aspect of this is the removal of obsolete and less safe cars or components from interchange operation like solid journal bearings, cast iron wheels, cast metal brake shoes, etc. 
  4. They establish criteria for repair or replacement depending on the extent of wear or damage.  Wheels representing the greatest maintenance and repair cost over the life of the typical freight car, Interchange Rule 41, “Wheels”, is instructive.  Among many other criteria, it states that wheels must be replaced when rim thickness falls below ¾” or 7/8” (depending on wheel size) or have thermal cracks in the flange or rim.  Similarly, Rule 12, “Brake Shoes and Shoe Keys”, states that brake shoes must be replaced when worn to 3/8” thickness or less. 
  5. If repairs are found necessary based on Section “A. Cause for Repairs” in the rule applicable to that component, appropriate repairs are defined in Section “B. Correct Repairs” of the same rule. 
  6. Each repair is assigned a Job Code at the end of the particular interchange rule.  In the Price Matrix of the Interchange Rules, commonly performed job codes are assigned a specific number of labor hours to perform the repair/replacement as well as a price for the component applied.  The hourly labor rate and component prices are updated annually and are uniform throughout the United States.  In 2015, for example, Job Code 1840, “Brake Shoe, Composition, High Friction 2 Inches”, established $6.70 for the cost of the new shoe plus 0.124 hours labor to perform the shoe replacement.  At the $120.54 standard labor rate, the labor cost to change the shoe was $14.95, for a total cost of $21.65.  Repairs for which standard hours have not been determined are billed at the actual number of hours expended times the standard labor rate. 
  7. A means is established to settle disputes over interpretation of the Interchange Rules and over whether one party was mistreated by another.  Perhaps another party performed (or claimed to perform) repairs on a car that the owner felt was unjustified under the Interchange Rules or charged an unjustified amount for the repair.  By signing the interchange agreement, car owners and repairing parties agree to submit such disputes to the Arbitration and Rules Committee (hence its name), whose rulings are final and absolute.  In addition to arbitrating disputes between different parties, the AAR also has a Mechanical Inspection Department which conducts unannounced audits of repair and inspection facilities.  I remember that at one time Conrail had to forfeit all its AAR billing from a particular location in Altoona for a specified period of time (one month, six months?  I don’t recall.) because of fraudulent billing. 


So, how are the Interchange Rules established, maintained, and updated?  As indicated in White’s book, they originated with the Master Car Builders Association in the latter part of the 19th century.  After several organization changes over the years, they are now under the jurisdiction of several technical committees within the AAR Safety and Operations Division.  Although at one time the AAR technical committees consisted solely of representatives of operating railroads, they now have members representing private car owners and suppliers.  Even though railroads now own less than 50% of interchange freight cars, railroads still retain a majority of voting members in each committee.  Since the railroads have to live with the results of any equipment failures out on the road, this is entirely reasonable in my opinion.  The Interchange Rules themselves, which are updated twice a year, are the responsibility of the Arbitration and Rules Committee.  The standards and specifications for cars and their components, which are made mandatory by reference in the Interchange Rules, are established by various technical committees.  Those committees are responsible for various aspects of freight cars and components such as brake systems, wheels and axles, couplers & draft gears, etc.  They, like the Equipment Engineering Committee of which I was a member for several years and Chairman in 2001 and 2002, make recommendations to the Arbitration Committee for any changes or additions to the Interchange Rules, but any actual changes to the rules are enacted by the Arbitration Committee.  Prices and standard labor hours are established by the Car Repair Billing Committee, which reports to the Arbitration and Rules Committee. 


Again, my thanks to Hudson Leighton for providing us with this list of changes to the requirements for freight cars and their components. 


Dick Dawson

A professional CV prepared by Mr. Dawson:

I have been a railfan for my entire life, but through pure coincidence I was able to take a job with the New York Central as an Assistant Engineer in the mechanical engineering department exactly one year, as it turned out, prior to the Penn Central merger. Following the merger, I transferred to Philadelphia to join the PC equipment engineering department.  Both the NYC and the PC were building freight cars in their own shops at the time, and I was quickly drawn into doing design work on them.  Among the cars I designed were the F50 coil steel cars and the X67  high-cube boxcars.  I left the PC to join Trailer Train in 1973.  I was hired as a research engineer but when the Railbox program of general service boxcars was started, I was transferred to that project because of my prior boxcar engineering experience in a company staffed with flatcar people.  After developing the Railbox specification I was hired by Berwick Forge and Fabricating to head their engineering department in 1977.  Berwick was primarily a boxcar manufacturer, but I also got involved with the Teoli bathtub coal gondolas which we built.  I stayed with Berwick Forge until 1984 when it went out of business following the virtual disappearance of the freight car market during the early 1980s.  The market for new freight cars has always been very cyclical, but the drop in the 1980s was extremely severe.  I was fortunate to be able to return to Trailer Train as Manager Quality Assurance but became Director Engineering & Research two years later when the incumbent retired.  I stayed with Trailer Train, whose name changed to TTX Company in 1991, until I retired from full-time work in 2003.  While at TTX, I developed the all-purpose spine cars, a series of heavy-duty and depressed-center flatcars, and two flatcars designed for auto rack service.  I represented TTX on the AAR Equipment Engineering Committee for 11 years and was its chairman for two years.  Before retiring I established the AAR Safety Appliance Task Force which wrote new regulations that superseded the FRA safety appliance regulations for new cars and continued as its chairman after retirement from TTX, working for the AAR until its work ended in 2019.  I did other consulting work for the AAR until 2020 and still do some work as an expert in litigation involving freight cars. - Dick Dawson

Dennis Storzek


Join main@RealSTMFC.groups.io to automatically receive all group messages.