This page categorize steam locomotives using a method not commonly seen -- by their color.
Before the 1890s, most if not all freight and passenger locomotives were painted in colors. Some, like Jupiter (think the driving of the golden spike), were painted very brightly while others were more practical earthy tones like greens and browns. Black locomotives became common beginning in 1880, after coal burning engines made grime commonplace. Black was chosen because black locomotives didn't show all the dirt and grime that covered the locomotive during normal use. After 1900, when a railroad line wanted to show off their locomotive(s), perhaps when used exclusively for passenger service, they would use special paint schemes to make them look more "attractive" or fast. This, of course, necessitated more frequent maintenance and cleaning and therefore, was not a common practice.
This page is mainly focused on colored North American steam locomotives. However, because the British (and a number of other countries) put more effort into coloring (or in this case maybe I should say colouring) their steam locomotives, a number of non-North American steam locomotives are also mentioned here. The LNER Mallard and the LNER Flying Scotsman are two good examples of coloured British steam.
The Central Pacific Jupiter and the Union Pacific 119 of the Golden Spike National Historic Site certainly have enough red in their paint schemes to qualify as red steam locomotives. These are the original paint schemes for these locomotives. These replicas were built back in 1980 by Chadwell O'Connor Engineering Laboratories of Costa Mesa, CA. The Jupiter is also one of the more attractive steam locomotives you will ever see.
The most well-known orange steam locomotives would the Southern Pacific Daylights. GS-4 Northern number 4449 has been in excursion service for many years. In my opinion, this is the most attractive streamlining ever applied to a steam locomotive. The colors used when 4449 was dressed up in the Freedom Train livery would also qualify this as a red, white or blue locomotive.
In 1946 the C&O converted four 25 year old F-19 Pacifics into class L-1 Hudsons (490-493). They had stainless steel and orange shrouds. 490 was the only one to see service after 1950. Its orange cowl was repainted yellow. C&O crews called these locomotives Yellowbellies. 490 is now on display at the B&O Railroad Museum in Baltimore, MD.
In 1941, the Chicago and North Western Railway had two of their class ES (superheaded) Pacifics fitted with streamlined shrouds which were painted in yellow and green. They were streamlined to pull the "400" express passenger trains between Chicago and Minneapolis. However, the C&NW decided to use diesels instead. The two streamliners were demoted to pull the Minnesota 400 and then local passenger service.
There are a couple well-known green steam locomotives in the USA. One is the beautiful Southern Railway class Ps-4 Pacific number 1401 on display at the Smithsonian Museum in Washington, DC. The other is the Southern Railway class Ms Mikado number 4501 at the Tennessee Valley Railway Museum in Chattanooga, TN. However, green is not the original color of 4501. 4501 is a freight locomotive and therefore was originally painted black. It was painted green to match that of Southern's passenger locomotives when it was put into excursion service a number of years ago.
The most famous blue steam locomotive in the USA is perhaps the Gulf, Mobile & Northern class P-1 Pacific number 425 that used to operate in excursion service on the Blue Mountain & Reading out of Hamburg, PA. Here is a shot of it under steam back in 1993.
Another very famous blue steam locomotive is the British Railways No 60022 'Mallard' (holder of the world steam speed record). This engine, with most of its class, was painted Garter Blue. During the war it was painted black and for a few years during British Railways days was in BR passenger livery of Brunswick Green. It is now preserved in its original Garter Blue by the National Railway Museum, York, England.
Ten of the J3 Hudsons (5445-5454) were built streamlined (in 1938). The design was developed by Henry Dreyfuss. Half of these locomotives had boxpok drivers. The other half had Scullin double-disc drivers. These locomotives were used primarily for New York - Chicago service. Shrouding over the main air reservoirs was removed in 1941. All streamlining was removed from these locomotives in 1945.
In 1964 CB&Q 5632 was painted with temporary (water-based) gold paint to help commemorate the 100th anniversary of CB&Q's suburban service. Chicago - Aurora runs were made on May 20, 1964 (a mid-week trip - on the actual day) and on May 23rd. The May 23rd trip consisted of a record number of passengers (about 3500) for a CB&Q fan trip (22 coaches were used). By June, 5632 was once again painted black. However, 5632 was again painted gold to celebrate the 50th anniversary of the opening of Kansas City Union Station with a trip to St. Joseph on October 31, 1964 and a trip to Bevier, Missouri on November 1. The trip on November 1, 1964 proved to be 5632's final (CB&Q excursion) trip for when she returned to Galesburg, she was stored unserviceable with no further extension on flue removal.
This photo was taken in 1967 at the PRR's Meadows Yards in Kearny, NJ. It may have been painted gold (or yellow) for "maintenance of way" service.
In 1937, West Burlington installed a stainless steel shroud and roller bearings on CB&Q 3002 in order to use it as substitute power on the Zephyrs. It was renumbered 4000 and named Aeolus (Greek God of the Winds). Crews were quick to refer to this locomotive as "Big Alice the Goon", after a character in the Popeye comic strip. 4000 saw regular duty heading the Chicago to Denver Aristocrat and Exposition Flyer. In 1941 West Burlington built a similarly shrouded Hudson 4001 also named Aeolus. 4000's shrouding was removed in 1941 but the nickname stuck. 4000 is now on display in a park in LaCrosse, WI without its shrouding.
The Union Pacific's Omaha Shops shrouded two locomotives in 1937. The 7002 locomotive was built to pull heavy passenger trains over the Rocky Mountains, with massive 6-foot wheels driven by 4,000 horsepower. The 2906 was one of 10 P-13 Pacifics built for the UP by Baldwin in 1920. They both were shrouded primarily to serve as relief power for the dieselized Cities streamliners between Omaha and Ogden or Denver. Pacific 2906 and Mountain 7002 served between 1939 and 1941 on the Forty-Niner, a heavyweight, all-Pullman streamliner departing five times a month from Chicago to the site of the Golden Gate Exposition in San Francisco. The locos bore UP's prewar streamliner colors of Armour Yellow, Leaf Brown, and Scarlet. The 7002 ended its spectacular 32-year career as a rescuer engine for stalled locomotives.