Hard to believe a month has passed since this neat thread was last approached. I note that the 6-18000 switcher has taken a serious nose dive in price. I missed one with loose wheels for $75 last week - busy flying and forgot to bid. And there exist a few at $175, new in the box. Won't be long before I snag one for 2-railing.
Do you suppose the newer K-Line derivative has become more popular, at the expense of this classic?