Monorail Patents

The monorail system was protected by a collection of patents all of which have expired in the US. The basic track element patents (straight track, curves, and the monoswitch) were filed first followed shortly by the track system (what I call the "geometry") patent. A patent covering the motors, bogies, and other railcar elements followed about six months later. The last relevant patent covering the various turnout designs followed three years later.

We can learn a lot about the design of the system by reviewing these documents. Did you know a suspended monorail similar to the Wuppertal Schwebebahn was considered? Figure 35 from US4861306A shows just such a design! And at figures 36a-h to see various track profiles which were considered (36a is the profile which was ultimately released). Another interesting idea was the integration of magnet couplers directly on the bogies (figures 26 & 28).

The first patent was filed on November 26th, 1986. Fees were regularly paid for many years. The last renewal fees were paid July 14th, 1999 after which the fees were unpaid and the patents expired. It seems by around 2000 the system had been completely written off as a viable part of the Lego company's portfolio.

The patents are available in the Patent Pack.

Element	Description	US Patent	Filing Date
	US4861306A covers the design of the rail (various style are discussed) as well as engine and railcar elements.	US4861306A	7/16/1987
	US5087001A covers turnouts, wyes, and crossover elements.	US5087001A	11/21/1990
	USD296806S covers the design of the long straight track piece.	USD296806S	11/26/1986
	USD296803S covers the design of the short straight track piece.	USD296803S	11/26/1986
	USD296804S covers the design of the large curve piece.	USD296804S	11/26/1986
	USD296805S covers the monoswitch (stop/go) track piece.	USD296805S	11/26/1986
	US4726515A covers track geometry such as the layout of curves.	US4726515A	2/25/1987