Car Service Rules, again

The Car Service Rules of the ARA and its successor, the AAR, are a topic of ongoing interest to many who attempt to mimic prototypical freight car handling. I’ve written about these rules before (see that post at: https://modelingthesp.blogspot.com/2012/01/car-service-rules.html ). The topic was large enough that I needed to complete the discussion in a follow-up post: https://modelingthesp.blogspot.com/2012/01/car-service-rules-2.html . 

Although those two posts were fairly thorough, there did arise further commentary some years later, as contained in a post discussing a comment to an earlier post; I wanted to clarify several aspects of the topic. (That post is here: https://modelingthesp.blogspot.com/2021/05/freight-car-handling-and-distribution.html ).

Just recently, I encountered several verbal discussions on the topic, most recently in the bar at the Cocoa Beach meeting two weeks ago (for a meeting summary, see: https://modelingthesp.blogspot.com/2025/01/cocoa-beach-2025.html ). As commonly occurs, there were several misconceptions and misunderstandings expressed in those discussion. Let me see if, once again,  I can clarify.

Let’s say you’re the Car Distributor at an Illinois Central yard in the St. Louis area. You have just received a car order for a 40-ft. box car to go to Seattle, to a consignee located on the Great Northern. The “empty” track in your yard has six box cars: two IC cars, and one each New York Central, MKT, Rock Island, and Western Pacific. What do you choose?

Let’s look at the rules. These were reproduced for decades in the back of each issue of the Official Railway Equipment Register, or ORER. You can click on this image to enlarge it if you wish.

As can be seen with a little thought, the purpose of these Rules was to reduce the number of empty miles run off by freight cars. If every railroad always loaded its own cars, and sent all foreign cars homeward empty, at least half the miles moved by the national fleet would be empty miles, of no benefit to anyone. In practice, these Rules were found to reduce empty miles to a little less than a third of all miles. In a sense, then, the Rules reduced the need for car purchases, through better utilization.

Now to our car order. Rule 1 says that you shouldn’t use the IC cars. For the further rules, you have to look back at the Bill of Lading, which includes the shipper-designated routing, via Wabash as far as Council Bluffs. That would be one railroad’s car you could use, the Wabash, so that the car could run off some miles on its own road, but you don’t have one. At Council Bluffs, the route designates UP, but you don’t have a UP car either. The routing designates UP as far as Portland, Oregon, then via GN to Seattle, but here again, you don’t have a GN car. This means you can’t follow Rule 2, 3 or 4.

We now consult Rule 5, to load a car to a Home District before or adjoining the destination District. Here is the official map (from the ORER), and the destination in District 1 adjoins Home Districts for the WP, in both Districts 2 and 5. So the right choice for this load is the WP car. The Rock Island car could be used also, as the adjoining District 5 of District 1 is a Home District for the RI.

What else may come into play? The empty NYC, MKT and RI cars could all be readily returned directly to their home rails in the St. Louis area, provided that there was no car shortage, so this could be a further reason to use the WP car for loading.

The example above is a little misleading, in only having a single car order to fill. In most situations, the IC Car Distributor would have several. From the Car Service Rules, you could expect the NYC car to be used for destination in the northeastern quadrant of the U.S., the Southern car for the southeastern quadrant, and the MKT car for the southwestern quadrant.

Modelers often think that a railroad would load the home-road car first, and that might be necessary on some occasions, but the Car Service Rules clearly prioritize using a car from quite far away from the originating point, as in the case described above. A consequence that may not be obvious is that on a layout like mine, an SP layout in California, loaded cars arriving from far away have a good probability of being SP cars, not cars from railroads in that faraway location.

For a somewhat different example, here is a Great Northern box car spotted at the type foundry on my layout (to learn what a type foundry is, you can consult this post: https://modelingthesp.blogspot.com/2018/05/whats-type-foundry.html ). The car came from Elizabeth, New Jersey and in accord with Car Service Rules, was routed to a Home District adjoining a Home District for the GN. The car, incidentally, has drifted a little into Alder Street, but should properly stand clear.

I should also mention a factor often overlooked by modelers: the state of the economy. When the economy is slack or in recession, each railroad tends to have more empties on hand than it needs, and priority goes to returning those empties; thus there are usually lots of empty cars to choose from in filling an order, and one can readily follow the Car Service Rules.

But when the economy heats up, cars tend to be in shorter and shorter supply. Then the Car Service Rules get ignored, in favor of getting your shipper the car that is needed. In such a case, you might fill the car order described above with an empty Southern box car, even though it would violate all six rules, if that was the only empty on hand. Railroaders sometimes called this provision “Rule Zero,” in reference to the Car Service Rules, as the most important rule: satisfy the shipper first.

Whether you choose to take these Rules into account in your model railroad layout, as part of car flow in operating sessions, is of course a personal matter, but it is one more component of achieving realistic operation.

Tony Thompson