Most likely you were looking at one of the "Heritage" units. This "Southern Green 'n Gold" with the white stripe was the passenger livery of the Southern Railway System of which I am proud to be an alumnus. I always thought that green was really pretty, and I saw plenty of it prior to merger in 1982 as I handed up orders to "The Southern Crescent" or loaded baggage as a Porter in Charlotte, NC. I was also privileged to deadhead aboard the E8's as I rode to assignments OR rode on Pass to various parts of the System.
If you have enough interest, perhaps you might like to do some research on this fine railroad that has received not near the credit it deserves in the industry for its contributions to railroads. One of its slogans was "Southern Gives a Green Light to Innovations", a slogan that was well-earned and well deserved. For example, while other railroads often struggled, Southern thrived and was known for its profitability and shrewd management as well the innovations it developed, particularly in the area of track maintenance. Southern was also listed in Standard and Poors not only in the top railroads in the US, but as one of the top 5 corporations to do so! It was the ONLY railroad to be so listed. It was truly a company to be proud of! Today, it lives as part of the Norfolk Southern Corporation, the other "half" of the conbined company. It continues to thrive!