Rivet Counter HO Scale Thrall 4727 Carbon Black Covered Hopper, Transportation Company of America

A byproduct of the petrochemical refining industry, carbon black is a fine, powdery substance with a consistency sometimes described as being akin to soot. Deep black in color, one of its major consumers is the automotive industry, where it’s used as filler in tires, belts, and other rubber products. It also sees usage as a pigment in inks, paints, and plastic products, all of which make it a popular commodity with a variety of industries. Hauling it, however, can be challenging thanks to its physical properties. Covered hoppers are typically used to handle carbon black, with unique designs dating back to the 1920s.

Found throughout North America, these unique freight cars are commonly found in large groups near major carbon black producers or users. They can also be seen singularly or in small blocks of cars in mixed freight trains. Both prototypes were painstakingly researched from field documentation, photographs, reference books, and builder drawings.

In 1992, Thrall introduced the 4727 cubic foot carbon black covered hopper. In contrast with the boxy 5750cf design, this newer design more closely resembles traditional covered hoppers. Similar in appearance to “high-hip” grain hoppers, these cars featured three bays, external posts, and “open” ends with visible slope sheets. Common with their larger 5750cf cousins, these 70-ton cars feature “butterfly” outlets, multiple round loading hatches on the car roof (22 or 28 depending upon customer specifications), and sampling spigots mounted into small indents in the car sides. Many of these cars are still in service today.

Reference: Carbon Black Cars: Freight Cars Journal Monograph #15 by Eric A. Neubauer, ISSN 0884-027X, 2100