From the inception of the Streamliner era UP has used yellow as the basic color on its psgr cars and engines. Until shortly before WWII the roofs, underbodies and trucks were brown. In 1941 the brown was changed to grey. At some point in the early fifties(?) the color of the trucks was changed to silver. Does anybody out there know the date (month and year will do) that this change went into effect.
jimrice4449
At Don Stracks Website is a page about
Union Pacific Diesel Locomotive Painting, Lettering & Numbering
Possible, it´s in the first line about the locomotives, the side is helpful for you too
http://utahrails.net/up/paint/up-diesel-paint.php
This is a part from this side:
1953-1957 – Aluminum Color On Trucks
The color used on locomotive trucks was changed from Harbor Mist Gray to Aluminum.
The aluminum color for trucks was first used on propane-fueled Turbine 57 in early June 1953. Harold Ranks took a photograph of Turbine 63 in 1954 with newly painted aluminum trucks. A photo of Turbine 55 in June 1955 shows it with aluminum trucks, and the revision of the painting diagram for Turbines 61-75 (new in March to October 1954) was changed in September 1955 to include aluminum trucks. Turbine 61 is shown in a November 1955 photo with aluminum trucks.
The first new passenger units with aluminum trucks were the four E9 cab units and 10 E9 booster units delivered in May and June 1954, numbered as UP 943-947 and UP 950B-959B.
The first new freight units with aluminum trucks were the 100 GP9s and GP9Bs in the 300-class from EMD, delivered between July and October 1957 (the painting diagram for these units is dated March 29, 1957, and shows aluminum-colored trucks).
With respect to passenger car trucks, photographic evidence shows that gray was still specified until the end of 1958 for newly-constructed cars.
On-delivery photos of storage mail cars 5711-5745 and baggage-express cars 5664-5678 (the last in November 1957) shows these cars with Harbor Mist Gray trucks. (See pp. 416-417 of Rank’s & Kratville’s Union Pacific Streamliners book.) Also, dome coaches 7011-7015 (delivered in November - December 1958) are shown in a builder’s or on-delivery photo (p. 501 of the Streamliners book) with gray trucks.
The first newly-delivered passenger cars with aluminum-painted trucks were cafe-lounges 5007-5016 (July 1959)(see p. 466 of the Streamliners book).
–John