The role of “foreign” cars in your fleet

Modelers often choose to model a prototype railroad that they particularly like, and then populate their freight car fleet with lots of cars decorated for that railroad. That’s perfectly all right, as far as it goes, because most railroads would in fact have a lot of their own cars on their own rails. But what about “foreign” cars, meaning cars owned by other than the home railroad? 

One issue is whether one should choose any old foreign railroads one happens to like,  or whether there are prototype patterns that ought to be modeled. Of course, like practically everything in model railroading, you can care or not care about the prototype. Here I’m addressing those who want to care.

If one wants to mirror prototype practice, one basic approach to this problem is called the Gilbert-Nelson approach, based on ideas first developed by Tim Gilbert and Dave Nelson. They had looked at extensive prototype information, particularly conductor’s time books, and realized that there was a pattern: many cars present in trains were numerically in proportion to the size of the owning road’s fleet, regardless of where in the country the data originated.

This means that a good first approximation to the choices of foreign road cars, and their relative abundance on the layout, is simply the size of foreign road car fleets. I show below a graph I’ve presented in several talks. These data are for 1950, and are modified from total car fleets by removal of ore cars, hopper cars, and ballast cars (as less frequent interchange cars in most part of the country). Especially as an SP modeler, the likelihood of coal-road hopper cars on my layout is pretty small and I neglect it. I have also separated out the refrigerator cars from Santa Fe, SP and UP. 

Of course, as Gilbert and Nelson fully recognized, this can only be true of free-running cars like box cars, flat cars and gondolas which are not specially equipped, and is likely true only on main lines. A coal branch, for example, will obviously be quite different. Still, this graph certainly identifies the major players.

My response to these major railroad ownerships is that I try in setting up operating sessions to make sure that there are always one or more cars from PRR and NYC present, and often B&O and Milwaukee also. Accordingly, when one sees something like the photo below, a gondola emptied of its cargo at the team track in East Shumala on my layout, there is a reason.

What about Santa Fe? As a strong competitor and rival of SP, any empty Santa Fe car would be directed promptly by SP crews back to Santa Fe at the nearest connection (for my layout, Los Angeles). But of course inbound Santa Fe cars, loaded all over the nation, certainly would appear on the SP, and I do include them in an inbound role in most sessions.

You may notice that Union Pacific is down at 12th in fleet size in the graph above. Because SP and UP were locked into a partnership on the Overland Route through Ogden, Utah, this might seem like a major source of UP cars on SP rails. But UP in those days was predominantly a bridge route, with relatively little originated traffic, so UP cars really would act like other faraway roads.

Are there other factors that come into play? One factor is whether the home road (SP in my case) had friendly or unfriendly relations with the railroads it interchanged with. It’s known that SP had friendly interchange relations with NP, RI and IC (at far ends of the system: Portland, Tucumcari, and New Orleans) in addition to the UP relationship mentioned above. 

The other important question to consider is the proportion of home road cars, vs. foreign cars. This does not seem to have a universal answer, and Gilbert-Nelson found different proportions in different places. 

There is an old rule of thumb, that home road cars may be a third to a half of all cars. I explored that point with some 1948–1952 time books (see, for example: http://modelingthesp.blogspot.com/2011/03/modeling-freight-traffic-coast-line_11.html ). What I found was in fact about a third for SP cars in California, and that’s supported also by photos. I have operated my layout on that basis, roughly one third home-road cars.

Needless to say, there is no reason for slavish adherence to any specific part of these ideas. There is much evidence that car identities could vary wildly from day to day in many trains or yards. But making an attempt to maintain an overall pattern on a layout makes sense to me, as a gesture to realistic railroad modeling.

Some discussion of this issue, predating Gilbert-Nelson, can be found in an article I published some time ago, copies of which can be obtained from the NMRA library. It is the source of data for the graph shown at the top of this post. If you’re interested, here’s the citation:

Anthony Thompson, “Railroad Freight Car Fleets," in Symposium on Railroad History, published by A.C. Kalmbach Memorial Library, NMRA, Chattanooga, TN, 1990, pp. 27–44.

Tony Thompson