Where's the real answer? None of the above, Norfolk Southern Railway was founded in January 20th, 1870 as the Elizabeth City and Norfolk Railway, and was reorganized as the Norfolk Southern in 1910! :teeth:
I was wondering whether this was a trick question or not. Matthew got it right as far as I'm concerned, the original "Norfolk Southern".
Both 1982 and 1990 are right, in a sense. From photos, I've observed that locomotives started wearing NS colors in 1982. However, pay careful attention. At first, NS engines were sublettered for NW, SOU, or one of the various subsidiaries. I recently deduced that engines delivered starting around late 1990 were the first to have NS sublettering. Engines built before that time still wear their old sublettering unless rebuilt.