Joy valve gear

Joy valve gear is a type of steam locomotive valve gear, designed by David Joy (3 March 1825 – 1903), Locomotive and Marine engineer, and patented (no.

[3] The drawing (right) shows the Joy gear as applied to a London and North Western Railway locomotive.

Joy gear was also used by John Fowler & Co. and several other steam traction engine manufacturers.

The most numerous locomotive class using Joy valve gear was Russian O class, in Od and OD variants (over 4,500 built) - a letter "d" / "D" in their designations stood for Joy (in Russian phonetically: Джой - Dzhoy).

There is a modified Joy gear designed by Henry Greenly for miniature railway steam locomotives.