Saturday, December 16, 2017

Understanding auto industry traffic

Any layout may have certain kinds of freight traffic that are distinctive, whether using special equipment, or carrying cargo with special needs, or operated in distinctive ways. The one I am going to discuss here is automobile industry traffic, both assembled automobiles and auto parts, because I know this was a significant traffic component of Southern Pacific’s Coast Route. But practically any specialized traffic on any layout could be analyzed in the way I am describing.
     I have addressed this topic in a number of previous posts, perhaps most generally in one about the relevant part of my freight car fleet (see it at: ). I have also summarized prototype SP auto-industry traffic on the Coast Route in a couple of places, most recently at this link: . But in the present post I want to delve further into specifics of the Coast auto parts traffic.
     I have relied on three main sources of information for my particular traffic. One is entirely generic and nationwide: the Walthers book, America’s Driving Force  (Walthers, Milwaukee, 1998). The book is long out of print at Walthers but is readily available from the usual on-line sellers of used books, such as AbeBooks ( ) and on auction sites such as eBay. It’s an excellent overview, both historical and modern. I’ll come back to the contents, but here is the cove:

The book is a full 8.5 x 11 inches in size. It can be criticized as a thinly disguised promo for Walthers structure kits, and that’s true, but it also contains a wealth of information about the auto industry.
     The second source is specific SP information that I drew upon in writing certain chapters in my volumes on SP freight cars (series entitled Southern Pacific Freight Cars), the ones about cars in assigned service for automobiles and auto parts. Specifically, these are chapters 6 and 7 in Volume 3, “Automobile Cars and Flat Cars,” Signature Press, 2004; and chapters 8, 11, 12, 13 and 15 in Volume 4, “Box Cars” (revised edition), Signature Press, 2014. These chapters contain numerous details and data about SP assignments for auto parts service. To illustrate with a single example, this photo from Chapter 12 of Vol. 4 (2014 edition) shows a Class B-50-30 car newly equipped with parts racks at the Detroit plant of Paragon, whose logo is at lower right. Note that the racks, purchased by SP to GM specifications, are stenciled “SPCO.”

From SP records. I know this car was in Buick axle service during 1953-54, and the car is lettered next to the door, “return to C&O Ry. Flint, Mich.,” so we know the railroad that served the Buick plant. And there was a Buick-Olds-Pontiac  assembly plant in Southern California at the time I model (see the first post cited in the second paragraph in the present post; I will show a more complete list below).  As I will show in a following post, this is already enough information to fill out a waybill.   
     To go beyond the explicit SP information of the kind just shown, one can turn to a helpful table in the Walthers book, America’s Driving Force, on page 56:

This show the company names and locations of a wide variety of parts suppliers, many supplying parts to more than one auto company (you can click to enlarge).
     As explained in America’s Driving Force, in the early days Ford was a very integrated company and relied on few outside parts suppliers, while General Motors was almost the opposite,using many of the suppliers listed in the table above, and more. Around 1950, Chrysler was closer to Ford than to GM in its use of parts suppliers, but was changing, as was Ford, toward a wide network of parts companies.
     This topic leads me to mention my third source of information, the Internet. As in so many research tasks, Google is your friend. Because auto plants and auto parts companies have employed so many people over the years, and been located in so many communities, the history of these many plants, including an immense list of ones now closed, is readily found on the internet.
     Use of the internet information, and tables like the one shown above, give you origins of parts shipments. The other half of the traffic story is the assembly plants, to which the parts moved. Those plants would also be the origin of shipments of assembled automobiles. Two paragraphs above I cited a link to an early list I made of auto plants. Shown below is a more complete list of California assembly plants at the time I model, 1953, and a few added historical details about the plants.

As I stated, these plants are the destinations for my auto parts traffic. (You can click to enlarge,)
     One last source of information for an SP modeler of auto traffic: Fred Frailey’s interesting and informative book, Blue Streak Merchandise (Kalmbach Books, Waukesha, WI, 1991). He emphasizes  how vital auto parts traffic was to this train by the late 1960s; but in contrast, he lists a train consist of June, 1953 (page 27), with 114 cars, only 13 of which carried auto parts, most for an assembly plant in Dallas. In later years, as SP captured the General Motors parts traffic to their two Southern California plants, an entire section of the BSM was called “Auto Parts West,” all GM parts. This emphasizes that information for your era is vital to understanding this or any particular traffic.
     I believe that this description of the information sources for SP Coast Route auto parts traffic provides sound and extensive background. I will go further and show example waybills prepared with this information in a following post. I should add in closing that my focus on the West Coast, and on the early 1950s, is only my own focus. Other eras and other parts of the country can be similarly researched.
Tony Thompson


  1. If you are referring to the term "auto industry traffic" in the context of the automotive industry, it does not typically refer to traffic on roads or highways. Instead, it usually pertains to the flow of activity, trends, and interactions within the automotive industry itself.

    1. I mean it exactly as you said, the traffic of the industry between plants, or en route to sale, not highway traffic.
      Tony Thompson