Armour Yellow on Union Pacific

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This page was last updated on October 29, 2022.

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Union Pacific and Armour Yellow

A review of Kratville and Ranks' book "The Union Pacific Streamliners" finds on page 300, part of a reproduction of a notebook from a painter at the Pullman factory. For Armour Yellow, the color given is DuPont 88-1743. Also, Pullman number 70-12.

Union Pacific's initial use of Armour Yellow was on its M-10000 Streamliner, delivered in February 1934. Other early Streamliners followed, and all used the same combination of Armour Yellow and Leaf Brown. The Leaf Brown color was changed to Harbormist Gray (or Grey) in 1940, prior to the delivery of E6 passenger units from Electro-Motive. In 1947 Union Pacific began using Armour Yellow on its cabooses, and on its diesel switcher locomotives. In 1952, UP began painting all passenger cars using Armour Yellow and Harbormist Gray (or Grey).

(Read more about UP's early diesel paint and lettering schemes)

The color remained unchanged until the mid 1980s, when the paint was changed to make it more environmentally friendly. The chemistry of the paint was changed by reducing volatile organic compounds (VOCs), along with the removal of lead-based Chromate Yellow, along with Cadmium and other heavy metals. The new color did not weather well, and needed to be protected with a clear coat. To give the appearance of being the same color, the actual color itself was changed to take advantage of the characteristics of its new clear coat protection.

"When I was promoted to the EMD Sales Engineering Dept. in the early 1970s, the Sales Engineer that handled the UP account, had his desk next to mine. When the federally mandated change to eliminate all lead in paint was enacted, my buddy had a hell of a time trying to explain to the Sales Manager that handled the UP account, in Omaha. The whole thing got so bad, that the UP Purchasing Dept. claimed that THEY would purchase the CORRECT Armor Yellow them selves, and have it shipped to EMD! Obviously even the "Great and Powerful UP" was unable to get ANY paint manufacturer to re-produce their famous Armor Yellow, without lead.  Thus, subsequent orders of EMD units for the UP, shipped with the "new" yellow." (Jack Wheelihan, posted to, June 21, 2022)

(Read more about UP's diesel paint and lettering schemes from the 1980s and later)

Armour Yellow Before 1934?

Armour Yellow (C.S. 22, No. 181) is *not* shown on the C.S. 22 color chip chart reprinted by the now-defunct Union Pacific Railroad Historical Society as part of their reprint of the C.S. 22 Painting Guide. The chip chart is dated January 20, 1923, with updates for October 26, 1923, March 30, 1929, and November 1, 1930.

These dates suggest that Armour Yellow did not exist on UP before late 1930, if not a couple years later.

Although research has not yet found definitive proof, conventional wisdom among Union Pacific historians is that Armour Yellow was the same as the color used to paint refrigerator cars owned by Armour Refrigerator Line (ARLX). At one time the largest owner of refrigerator cars, Armour Refrigerator Line, its Armour Car Line parent, and Armour & Company, the top level company, were all controlled by the same interests, and were all subject to antitrust actions in the 1905-1920 time frame. These antitrust actions split the company interests, but ARLX continued in business moving mostly meat products in the Midwest. A group of 2000 steel cars (the only steel cars owned by ARLX) were delivered in 1948-1949, and were reported as being painted with Armour Yellow as their body color. (See "Armour Refrigerator Line's Steel Reefers" by Ed Hawkins, Railway Prototype Encyclopedia, No. 21, page 108)

Armour & Company was established in Chicago as a meat packing house in 1867 by the Armour brothers, led by Philip Danforth Armour. In 1883, Philip Armour created the Armour Car Lines, including Armour Refrigerator Line, to transport his own meat products and produce. By 1900, Armour had its own car manufacturing plant in Kansas City, and owned 12,000 cars, one-third of all refrigerator cars on the nation's railroads. After the senior Armour's death in 1901, his son, J. Ogden Armour ran the Armour enterprise with much success.

In 1919, Armour & Co. was forced to sell a portion of its car fleet after an antitrust decision by the Federal Trade Commission of unfair advantage. The sale was to Fruit Growers Express, a new company organized in March 1920 for the purpose. FGE was jointly owned by 10 major railroads, including Southern, Atlantic Coast Line, Baltimore & Ohio, and Pennsylvania, taking its name from the name of one of the many car lines that Armour had established in the 1890s. Included in the sale were over 4200 pieces of rolling stock, Armour's repairs shops at Alexandria, Virginia, and Jacksonville, Florida, and numerous ice plants and other facilities scattered throughout the East Coast.

As a related siude note, in 1907, after Pacific Fruit Express was formed by Union Pacific and Southern Pacific in 1906, Armour sold its facilities in California and other western states to the new PFE.

During the period of 1930-1934, when UP likely adopted its signature Armour Yellow color, Armour Refrigerator Line (ARLX) had approximately 6,000 refrigerators cars in service, numbered among the ARLX 6000-16999 series numbers. Jack Mullen wrote in August 2015 that in July 1935 there were a total of 6,527 ARLX cars, including 420 tank cars and 200 stock cars, and 5,907 reefers.

Research In 1970

The following comes from an original document by John Weatherby in Union Pacific public relations files, dated May 6, 1970 (code is 050670w) (courtesy of Thornton Waite, February 24, 2002):

  1. Instructions were issued in June 1947 that when CA-3 and CA-4 class cabooses, series 3700-3899 required repainting, they should be repainted with Armour Yellow and Freight Car Red. Previous to this time all cabooses were painted red, and lettering was white.
  2. For a brief period, from June 1948 to May 1949, a few of the steam locomotives which were painted two-tone gray, had Armour Yellow striping; however, since April 1950, gray striping enamel with black edging was used. Reason for yellow stripes cannot be determined.
  3. In the period 1946-1950, only cars in Streamliner service (C&NW-SP-UP, later Milw-UP-Wabash) were painted yellow-gray-red scheme.

Other Users Of Armour Yellow

(Portions first published to the UP Modelers and Union Pacific Yahoo discussion groups on June 11, 2003)

The Armour Yellow color was also used by General Motors on their Chevrolet line of pickup trucks, from 1936-1952. For the 1939 models, the color was used as the body and box color, along with a blue color for the body stripe called "Export Blue," with the fenders and running boards being black. Another combination in 1940 was Armour Yellow matched with Omaha Orange, a color well known to Great Northern fans. (, "Paint Colors for 1939 Chevy" by Keith Salter and Whitney Haist)

Many may agree that the Armour yellow name comes from a similar color, if not the same color, being used on Armour refrigerator cars. The concurrent use by GM of the apparently same color brings up the question about the true origins of Armour yellow. The color used by GM was known as DuPont Dulux Yellow Enamel. Maybe it was a standard DuPont color readily available to General Motors, and UP simply selected the color for its new M-10000 Streamliner and added their own Armour Yellow name to it.

Research has found that Armour Yellow was known as DuPont No. 93-3421 Dulux Yellow Enamel. The same color was used by Akron, Canton & Youngstown on their four H20-44s from Fairbanks Morse after the road's officials saw the UP H20-44 in July 1947 at the Railway Equipment expo in Atlantic City. The same yellow was also used by Atlantic Coast Line, Detroit & Toledo Shore Line, Erie, Kansas City Southern, Louisiana & Arkansas, Meridian & Bigbee, and Phelps-Dodge Morenci Mine.

(Armour Yellow was used on Chevrolet pickups, 1936-1952 -

(Armour Yellow was used on Dodge trucks, DuPont 93-55092 -

Other railroads that used Armour Yellow include Florida East Coast Railway, which used the color on their passenger locomotives into the 1960s. (information from Ken Olsen via email to Dick Harley on March 22, 2008)

Joe Braun wrote on the Erie Lackawana email discussion group on August 2, 2008:

We know that Erie yellow was stock DuPont Dulux Yellow. With John Bezuyen doing the research and painting, this fact was underscored, so the New York & Greenwood Lake Railway Geep and RS wear the modern version, still Dulux Yellow 9356d.

Research done by the UPHS and AC&YHS shows that Erie Yellow and Armour Yellow were the same paint.

Take that stock Dulux Yellow, make it the prime color in a scheme with red and gray (brown at first), call it "Armour Yellow" and use it on hundreds of cars in a famed Streamliner fleet, weather it with the ruddy hues of western dust, and photograph it enough on Kodachrome film in late afternoon sun - and Armour Yellow takes on a life of its own. Armour Yellow was the same yellow that adorned Erie black and yellow diesels. It was, as it always looked to me in person trackside, simply a good and hearty "yellow."

DuPont Color Codes

As mentioned above, Armour Yellow was DuPont Master Color Code 9356, also known as DuPont No. 93-9356 Dulux Yellow Enamel. Other information taken from sources for automotive colors has found that DuPont 202-xxxx and 246-xxxx color codes were Duco (spray paint only), and 93-xxxx color codes were Dulux. Research during 2003 found that DuPont 88-xxxx is for brushable Dulux, and 234-xxxx is sprayable Dulux.

This suggests that UP Armour Yellow was color code xxx-9356, regardless of the the application technique.

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