Climax
With an unusual name, the Climax locomotive was a product of the Climax
Machinery Company (Corry, PA). Designed by Charles D. Scott, with some patents
from George Gilbert, production began in 1884. The Climax was similar to
the Heisler, in that a longitudinal center shaft drove each set of trucks.
There were two cylinders - one on each sde - usually canted upwards at about
25 degrees. These in turn drove a flywheel connected by a shaft to a set
of bevel gears.
Climaxes never reached the popularity of the Shay. Perhaps due to the relatively smaller size (the largest was only 100 tons), or the rather characteristic "jackhammer" ride, only about 1,100 were built before production ended in the late 1920s. Only 18 survive to this day.
Curiously, the original Gilbert patents had cylinders in a "V" arrangement, similar to a Heisler. Gilbert eventually went on to the Dunkirk Engineering Company.
To see a narrow gauge (HOn30) model Class A Climax choose
this link.