Another reason why steam locomotives were painted black was because for a long time, nobody could make paint that could stand up to the smokeboxes' hot temperatures. Eventualy somebody developed an aluminum-like color that could, but some railroads stuck with black or a very dark gray until the bitter end.
Not really an explanation as to why the entire locomotive was painted black. Besides, hardly any locomotives used aluminum paint on the smokebox/forebox. Most used the boiled linseed oil and graphite that Hot references. This could vary from a light grey to a dark black.
As noted, locomotives in the beginning were quite colorful. The Victorian era saw locomotives painted in all shades, from blues, yellows, greens, and even pinks, as shown above. Brass was all over the place. Elaborate pinstripes adorned wheel spokes, cabs and domes. The UP 119 even features several detailed oil paintings on the sand dome and tender! In this era, locomotives were permanently assigned to an engineer, who often spent many dollars out of his own pocket to personalize his steed with extra bling (You see the same mindset at work today with long-haul truckers and their tractors). Engineers back in the day paid the ashcats to polish their engines every night with oily rags.
How about red drive wheels? Red was one of the most expensive colors of paint there was (and still is!), and if you wanted to show off, this is the color you used. The same reason firemen painted their fire engines this color--it was a source of pride!
After the death and devastation of the Civil War, locomotive decorating schemes became a little less flamboyant. You saw less brass, less striping, darker colors. Baldwin engines started using a dark olive color (which appears black in B&W photos). And, as the story goes, the pinchpenny New York Central eventually started painting the entire engine black, which did save enourmously in the cleaning department. Other railroads soon followed suit.
No, locomotives were't always black. And neither were Model Ts!
