Covered Hopper, 3-Bay, Thrall 4727

History: 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.

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. Reference: Carbon Black Cars: Freight Cars Journal Monograph #15 by Eric A. Neubauer, ISSN 0884-027X, 1990

Railroad/Company: Thrall Car Manufacturing Company was a manufacturer of railroad freight cars in Chicago Heights, Illinois from 1917 to 2001. The company was sold to Trinity Industries in 2001. A.J. Thrall established the Union Wagon Company in 1916, selling used and reconditioned rail car components. This became the Thrall Car Manufacturing Company in 1917. By mid-century, under the leadership of Richard L. Duchossois, the company focused on building specialized freight cars, such as high-cube boxcars for auto parts, all-door boxcars for building products, gondolas, rotary-dump gondolas for coal, bulkhead flatcars and centerbeam flatcars for lumber, double-stack container cars, covered hoppers, autorack cars and single-level trailer cars. In the 1980s, Thrall acquired five competing railcar manufacturers, including autorack builders Whitehead & Kales and Portec, and became the largest such manufacturer of these cars in the United States. In 1984, Duchossois purchased the remaining shares of the company owned by the Thrall family, and the company then operated as part of Duchossois Industries. In the 1990s, Thrall had a production capacity of over 16,000 freight cars per year, with more than 3,000 employees.

From 1997, a European subsidiary Thrall Europa manufactured wagons in York, UK. Thrall Europa, York works closed 2002. In 2000, Thrall Europa acquired the railway vehicle manufacturer ČKD Vagonka Studénka (Czech Republic), renamed Thrall Vagonka Studénka. In 2006 Trinity Industries sold off its European operations to International Railway Systems. The closely held company was sold to Trinity Industries, based in Dallas, Texas, in 2001. The company was subsequently renamed Trinity Rail Group, LLC.

From Wikipedia