A Climax locomotive is a type of geared steam locomotive in which the two steam cylinders were attached to a transmission located under the center of the boiler. This transmits power to driveshafts running to the front and rear trucks.
Rush S. Battles patented the basic design in 1891. Battles’ design had horizontal cylinders connected to the drive shaft through a 2-speed transmission. The drive shaft passed just above the axle centers, requiring the use of hypoid bevel gears to transfer power to each axle. Unlike the later and somewhat similar Heisler design, there were no side rods on the trucks and all gearing was open, exposed to the elements. Battles’ patent describes the core design that became the Class B Climax, and as his patent illustrations show the name Climax emblazoned on the locomotive cab.
Charles D. Scott, an inventor who had previously proposed a less successful geared steam locomotive, patented improved versions of Battles’ trucks in 1892 and 1893.Scott’s 1892 patent was the basis of the Class A Climax. His 1892 patent included gear-case enclosures.
Many loggers considered the Climax superior to the Shay in hauling capability and stability, particularly in a smaller locomotive, although the ride was characteristically rough for the crew. Mendocino Lumber Co. owned one of the two Climaxes along the Mendocino Coast – Caspar Lumber Co, owned the other.