Are there any articulated spine or well cars with an even number of units?

According to an article I just read on this site, there have been some 1200 pairs of 89' flats articulated to carry three trailers (with one over the middle truck). But are there any articulated spine or well cars with an even number of units? I've seen lots of 3-unit and 5-unit cars but never any with 2 or 4 units.