Climax Class C Logging Locomotive

[Oswald Lemus]

Theinvention of the Climax locomotive is attributed to Charles D. Scott, who ran a forest railway near Spartansburg, Pennsylvania between 1875 and 1878. A lumberjack of considerable mechanical ingenuity, Scott sought to bring an improved logging locomotive of his own design to market and brought the drawings to the nearby Climax Manufacturing Company in Corry, Pennsylvania. The first four Climax locomotives were built and delivered in 1888. The design patent[1] was filed in February in the same year and granted in December. The invention was not patented in the name of Scott, as he had only a limited education, so he left the drawings to his brother-in-law George D. Gilbert, who was a civil engineer by profession and worked for Climax. Gilbert had the invention patented in his name without mentioning Scott.[2]

Gilbert's patent[1] specified an upright maritime-type two-cylinder steam engine, a 2-speed transmission and a drivetrain in the underframe passing just above the axle centers. The patented differential for transferring the power from the drive shaft to the wheels was only used in the first Climax locomotives. In a similar way to that used in an automobile, the force was transferred to the two wheels of an axle separately, with one wheel being firmly connected to the wheelset shaft and the other wheel being able to rotate loosely on a sleeve around the shaft. The idea of the differential transmissions was to reduce resistance on tight bends by allowing one wheel to turn with fewer revolutions than the one at the other end of the axle. The design did not prove workable, because when driving at the adhesion limit, less tractive effort could be exerted compared to locomotives with rigid wheelsets.[2]

Rush S. Battles patented the basic design of the drivetrain without the differential, using simple hypoid bevel gears to drive the wheelsets with normal fixed wheels.[3] Unlike the later, somewhat similar Heisler design, there were no side rods on the trucks and all gearing was open, exposed to the elements.

A further patent[4] from 1891 describes a locomotive with horizontal cylinders connected to the drive shaft through a 2-speed transmission. Battles's patent describes the core design that became the Class B Climax, and his patent illustrations show the name Climax emblazoned on the locomotive cab.

Charles D. Scott, who had previously proposed a less successful geared steam locomotive,[5] filed a lawsuit against Gilbert and Battles and applied for a patent in his own name, which was granted to him on 20 December 1892 after a lengthy legal dispute. But the lawsuit left Scott penniless because he could hardly benefit from the invention.

Scott's patent[6] showed the arrangement of the steam engine, boiler and two-speed gearbox in accordance with Gilbert's patent[1] while the drive without differential gearbox was described in accordance to Battles' patent.[3] Scott's patent corresponds to the most common design of Class A Climax locomotives.

In 1893, Scott proposed a geared steam locomotive, in which the frame of the boiler was hinged to the frame of the tender. The running gear underneath the boiler was firmly connected to it and was driven by common lateral cylinders and side rods. Underneath the tender was a truck which was similar to the Climax locomotives driven by a central shaft which took the power from the front axle of the locomotive via a hypoid bevel gear. For the first time, the design used closed axle drives with housings on one hand protecting the gear unit from and on the other hand also containing the gear lubricant.[7]

All Climax locomotives were built by the Climax Manufacturing Company (later renamed to the Climax Locomotive Works), of Corry, Pennsylvania. In addition, an agency and service facility was established in Seattle, Washington to sell and maintain locomotives for west coast buyers. Production began in 1888 and the last Climax locomotive was produced in 1928. Between 1,000 and 1,100 were built.

Many loggers considered the Climax superior to the Shay in hauling capability and stability, particularly in a smaller locomotive. This was due to its fully sprung truck arrangement; the Shay locomotive had no springs on the bogie on the drivetrain side and was therefore not fully able to compensate for twists in the track. The ride on the large class C Climax was characteristically rough for the crew, since the imbalance of the large drivetrain could only be compensated at one speed.[8]

Introduced in 1893, the Climax Class B was looking more like a conventional steam locomotive. It had the cylinders on both side of the boiler, permitting it to be longer and larger than possible with the Class A arrangement. The two cylinders drove a transverse shaft that was geared to the longitudinal driveshaft in the middle; on early Class B Climaxes, the cylinders were horizontal and pointing forwards, while later ones had the cylinders angled upwards at about 30 degrees from horizontal. Class B Climaxes weighed approximately 17 tons at minimum to a maximum of approximately 60 tons.

A class C was a three-truck design, the additional powered truck being beneath a water-carrying tender articulated to the locomotive. This allowed the locomotive to operate for longer periods of time before needing to stop for water. All Class C locomotives had inclined cylinders.

Scott decided to place his locomotive on the market and took his plans to the Climax Manufacturing Company in Corry to have the locomotive built. The first known Climax was out-shopped in March 1888 and was sold to the firm of Imel, Powers and Shank. Three more were built and sold within the next three months. A patent was applied for on February 10, 1888 and granted December 4, 1888, however, the patent was issued to George D. Gilbert instead of Scott.

The first Climax Locomotives built were very crude in appearance and bore little resemblance to conventional locomotives. A vertical boiler and two cylinder marine type engine was mounted on top of a platform frame, supported by a four wheel truck at each end. A round water tank was placed on one end and a fuel bin on the other. Power was transmitted to the axles by gears with a differential arrangement similar to the modern automobile, and driven by a line shaft connected to the engine through a two speed gear box. The frame, canopy type cab, and even the truck frames were made of wood.

The first Climax locomotive weighed ten tons in working order, and was soon increased to fifteen tons. It also set the pattern for the Class A type, which became so popular and was built until the plant went out of business.

The most outstanding feature of the Class A Climax was the two speed gear arrangement connecting the engine to the longitudinal line shaft which in turn connected with the axles, centered between the wheels. These gears had two speeds, high and low, which could be shifted at will by the engineer in the cab. The low speed was a decided advantage when a heavy train had to be started on a grade, or when climbing a steep grade. The low speed gear ratio was 9:1 providing 13,200 pounds tractive effort and the high gear ratio was 4.5:1 resulting in 6,600 pounds tractive effort. They also had a neutral position which could be used to allow the locomotive to roll freely down grade by gravity. However, this was not recommended on steep grades.

The Class A locomotive had an operating speed of six to ten miles per hour depending on which gear was used. This was slower than the larger Class B and C Climax and other makes of geared locomotives, but was ideal on poor track. All three classes of Climax Locomotives used the same type of trucks. The design used on the Climax truck was the most flexible ever used on any geared locomotive and the center drive allowed them to swivel freely and negotiate the sharpest of curves. The line shafts crossed the axles in the center and were held in place by cross boxes and bearings. This arrangement, plus the springs over each journal bearing, would allow the axles to move up and down on rough track without the slightest binding of the gears which always remained in perfect mesh.

The Class A locomotives were always small and were standardized in twelve, fifteen, eighteen and twenty-two tons sizes. Its combination of low speed and flexible trucks with its light weight, allowed it to run on the lightest rail and rough poorly constructed track with ease and haul a heavy load. In comparison with its weight, it was a very powerful little engine.

The appearance and appliances of individual Class A locomotives varied considerably. The original open frame canopy style cab was often modified by the owner and was later changed to an enclosed cab by the manufacturer. A few were built with cabs that completely enclosed the locomotive. Larger capacity square water tanks could be ordered and in fact became the standard in the last years of production. Headlights could be any number and mounted in various locations. Bells were rare, but were applied in several instances. The spark arrestors varied from a simple wire screen cage fastened on the top of the stack, to a distinctive Climax style diamond stack. Quite a few Class A locomotives had no spark arrestor at all.

The Class A Climax was constantly improved over the years and the vertical boiler was eliminated. It was first replaced with a round fire box tee shaped boiler, then a square fire box tee boiler, followed later by a taper shell type boiler and finally a larger straight shell type. In 1911, the main frame was redesigned with steel and offered as an option. After it became available, only a limited number were built with wood frames. In 1916, the round water tank was replaced by a larger square water tank.

A small type A Climax was also designed which weighed seven to eight tons. It was basically like the larger engines except that it only had two axles and four driving wheels and did not have the speed gear shift. About four of them were built, but they did not prove successful because of being too light for most logging railroad operations.

3a8082e126