Are there any significant differences in the several Lionel E6 AA pairs produced since 2001?
The Southern, Rock Island, and Atlantic Coast Line are the first three produced I think with the Santa Fe, Burlington E5, and Milwaukee Road following later.
The Santa Fe's had a brief period a few years ago where two or three sets ran way up to a supposedly artificial price on the popular auction site. Then several more sets sold for just under a grand but sanity seems to have returned as a pair closed last week from Trainz for a much more reasonable $481.