I believe thats an EF81 Cassiopeia. I also think it was a Limited release and not retail but I could be wrong. I always thought this train to be odd as the middle car which has a forward facing observation window where all you can see is the rear of the engine.
thanks for your comment - there was one on sale here in the uk, used but in good condition, unfortunately i missed out bidding. I suppose it is also strange to have what I think of as a freight train hauling passenger coaches.
there are several engines type in JR pull both freight and passengers trains. DD51 is a notable example.