A Climax locomotive is a special type of steam-powered train engine made by the Climax Manufacturing Company, which later became the Climax Locomotive Works in Corry, Pennsylvania. These engines had two steam cylinders connected to a transmission under the middle of the boiler. The transmission sent power through driveshafts to the front and back trucks. About 1,000 to 1,100 of these locomotives were made in three different classes: A, B, and C, between 1888 and 1928.

Invention and production

The Climax locomotive was invented by Charles D. Scott, who operated a forest railway near Spartansburg, Pennsylvania from 1875 to 1878. Scott, a lumberjack with strong mechanical skills, wanted to create a better logging locomotive and shared his designs with the nearby Climax Manufacturing Company in Corry, Pennsylvania. The first four Climax locomotives were built and delivered in 1888. A patent for the invention was filed in February 1888 and approved in December of the same year. Scott did not apply for the patent himself because he had limited education. Instead, he gave his drawings to his brother-in-law, George D. Gilbert, who was a civil engineer and worked for Climax. Gilbert filed the patent in his own name, without mentioning Scott.

Gilbert’s patent described a vertical steam engine, a two-speed transmission, and a drivetrain located below the locomotive’s frame, just above the axle centers. The patent also included a special gear system called a differential, which helped transfer power from the drive shaft to the wheels. This system allowed the wheels on one side of an axle to rotate at different speeds when turning sharply, similar to how car wheels work. However, this design did not work well because the locomotive could not pull as much weight as other locomotives with rigid wheelsets when moving at the maximum grip on the tracks.

Rush S. Battles later patented a simpler version of the drivetrain without the differential. His design used basic gears to connect the wheels, and the locomotive’s wheels were fixed in place. Unlike later designs, such as the Heisler, Battles’ locomotives did not have side rods on the trucks, and all gears were exposed to the environment.

A patent from 1891 described a locomotive with horizontal cylinders connected to a two-speed transmission. This design became the basis for the Class B Climax locomotives, and the patent drawings showed the word “Climax” on the locomotive’s cab.

Charles D. Scott, who had previously created a less successful locomotive, sued Gilbert and Battles over the patents. After a long legal battle, Scott was granted a patent in his own name on December 20, 1892. However, the lawsuit left Scott with no money because he could not benefit from the invention.

Scott’s patent included the arrangement of the steam engine, boiler, and two-speed gearbox as described in Gilbert’s patent. It also included the drivetrain design from Battles’ patent. This combination matched the most common design of Class A Climax locomotives.

In 1893, Scott proposed a new locomotive with a hinged boiler frame connected to the tender’s frame. The wheels under the boiler were fixed and powered by side rods and cylinders. Under the tender, a truck was used, similar to Climax locomotives, and powered by a central shaft connected to the front axle through a gear system. This was the first Climax locomotive to use closed axle drives, which protected the gears and held the lubricant inside.

All Climax locomotives were built by the Climax Manufacturing Company, later renamed the Climax Locomotive Works, in Corry, Pennsylvania. A service center was also established in Seattle, Washington, to sell and repair locomotives for buyers on the West Coast. Production began in 1888 and ended in 1928. Between 1,000 and 1,100 Climax locomotives were built.

Many loggers believed the Climax locomotive was better than the Shay locomotive for moving heavy loads and staying stable, especially in smaller models. This was because the Climax had fully sprung trucks, which helped absorb track imperfections. The Shay locomotive lacked springs on the drivetrain side of its bogie, making it less stable on uneven tracks. The large Class C Climax locomotives had a rough ride for crews because the heavy drivetrain could only balance properly at one speed.

Classes

Climaxes were built in three distinct classes:

Class A Climaxes had a steam engine with two vertical cylinders in the center of the locomotive. These locomotives had a frame similar to a flatcar, with wooden boxcar-style bodywork built above it to protect the crew and fuel from the weather. The front part of the locomotive, before the engine unit, held the boiler. At first, the boiler was vertical, but between 1893 and 1895, the design changed to use a rounded "tee" style boiler. Around 1904, the design changed again to use a square "tee" style boiler instead.

At first, Class A Climaxes had wooden frames. By 1911, steel frames became available, but they increased the cost. Most Climaxes had at least two bogies, but some designs had only four wheels. Class A Climaxes were small, usually under 17 tons. Unlike Heisler and Shay locomotives, Class A Climaxes had two-speed gearboxes. Class A Climaxes were not always built before Class B and C models, even though they shared the same naming system.

Because they were lighter than Heisler and Shay locomotives, Class A Climaxes were well-suited for pole roads. These locomotives had double-flanged wheels shaped like cones to help them stay on rough log tracks.

Class B Climaxes were introduced in 1893 and looked more like traditional steam locomotives. Their cylinders were placed on both sides of the boiler, allowing for a longer and larger boiler than Class A models. The two cylinders powered a transverse shaft connected to a longitudinal driveshaft in the middle. Early Class B models had horizontal cylinders, like traditional locomotives, but they drove a counterweight above the wheels. This design was later replaced with a simpler version where the cylinders were angled at about 30 degrees without the counterweight.

Class B Climaxes initially weighed between 17 and 35 tons. Models weighing 17, 20, and 23 tons had T-shaped square fireboxes with steam domes on top inside the cab. By 1910, steel cabs were available for Class B models. By 1915, Walschaerts valve gear became an option, replacing the earlier Stephenson gear. Class B locomotives eventually reached weights of up to about 60 tons. Although their maximum speeds were not listed, they were believed to travel at around 15 miles per hour.

Class C Climaxes had a three-truck design, similar to Class B models, but with an additional powered truck beneath a water-carrying tender attached to the locomotive. This allowed the locomotive to run longer without stopping for water. All Class C locomotives had inclined cylinders.

Survivors

About 17 Climax locomotives remain in North America, with around five still working.

• Two are in Australia: Number 1694, restored and working since September 8, 2013, at the Puffing Billy Railway in Belgrave, and Number 1653, on display in Hobart, Tasmania.

• In New Zealand, four Climax locomotives remain out of seven originally delivered. These include Number 522 in Tokomaru, Number 1203 in Shantytown Heritage Park near Greymouth, Number 1317 being restored in Te Awamutu, and Number 1650 under restoration in Pukemiro since 2013.

• Climax Number 9 (shop number 1551, previously More-Keppel & Co. #6 and Middle Fork Railroad #6) operates at the Cass Scenic Railroad State Park in West Virginia. It works with Shays to pull excursions up Cheat Mountain from May to November. This is a 70-ton Class C Climax locomotive.

• The White Mountain Central Railroad in Lincoln, New Hampshire, uses Climax Number 6 (shop number 1603, previously Woodstock Lumber Co. #6, Parker-Young Co. #6, Beebe River Railroad #6, and East Branch & Lincoln Railroad #6) as its main locomotive during summer. This is a 50-ton Class B Climax with Walschaerts valve gear.

• The "Durbin Rocket" (shop number 1059, previously Moore-Keppel & Co. #3 and Middle Fork Railroad #3) on the Durbin and Greenbrier Valley Railroad in Durbin, West Virginia, is pulled by a Climax during regular excursions. This is a 55-ton Class B Climax with internal Stephenson valve gear.

• The Corry Area Historical Society’s Museum in Corry, Pennsylvania, displays a Class B Climax in its exhibit room, placed on a section of track.

• A restored Climax locomotive is on display at the Railroad Museum of Pennsylvania in Strasburg, next to a Heisler and a Shay locomotive. These are not working.

• In Canada, two Climax locomotives are preserved at the BC Forest Discovery Centre in Duncan, British Columbia. Shawnigan Lake Lumber Co. Number 2 is a 25-ton Class B locomotive built in 1910 as shop number 1057

Conversions

Some Climaxes, especially Class A, were later changed to use diesel or gasoline fuel. Some of them are still around today, using the original frame and drive mechanism.