Like competitor MTH Electric Trains, MDK was a large Lionel dealer, and its mail-order ads appeared in magazines such as Model Railroader in the late 1970s.
In an oft-repeated story, Maury Klein and his plant manager, Brent Chambers, found the molds for the Marx model 333 and 1829 4-6-2 locomotives in a dilapidated Fisher-Price warehouse near Buffalo, New York in 1984.
During the 1980s, K-Line filled much the same role that Marx had in the model railroading arena, supplying similar trains at a lower price than Lionel, but with less prestige.
Shifting its emphasis away from its budget offerings, K-line made some of the very best mass-produced O scale trains with their detailed models that it released in its latter years.
K-Line's S gauge offerings provided budget-priced cars as well as the already produced track compatible with American Flyer-brand trains.
Unlike its latest O scale products, K-Line's marketing on its S gauge cars centered its price advantage over the competition.
The two companies settled the suit on August 10, with K-Line agreeing to withdraw the infringing products by January 31, 2006 and paying a royalty to Lionel in the interim.
Increasing amounts of scale products, including some of the well known 21-inch alumumum passenger cars, were added late in Lionel's license period.