Three-Speed and Reverse Gearbox
This is similar to the gearbox by Mr. Adrian Hall in the January 1976 issue of Meccano Magazine. The ratios for the 1st and 2nd gears are however 4:1 and 2:1 instead of 9:1 and 3:1. In the magazine a special coupling was used for 3rd gear to connect directly to a socket coupling. However, a dog clutch works perfectly well and was not mentioned in the article.
The selector rods are held in position by pulleys with sprung rods bearing down on them, instead of cut and bent plates — an idea I borrowed from the epicyclic gearbox by Brian Elvidge.