A traction engine is a type of portable steam engine that is similar to a locomotive, but able to travel along roadways and other firm surfaces. This self-propelled machine was primarily utilized during the 19th century to pull loads, plow ground, and provide mechanical energy in remote locations. Early versions of this device employed a chain drive mechanism, but a gear-driven version soon became the industry standard. The first traction engine was invented in the 1860s as an alternative to the horse-drawn portable steam engine and was widely used until the 1920s. Use of the steam-powered traction engine declined in the 1930s as gasoline-powered machinery became more practical.
A traction engine is similar to a locomotive engine because both machines are steam powered. While a locomotive engine is strictly confined to the railway, traction engines can travel freely along any firm surface. This freedom of movement makes them useful for a variety of agricultural and industrial applications. This steam engine is designed in several different ways according to its primary use. Each design typically includes a flywheel-driven pulley for powering a separate piece of machinery and a draw-bar for pulling loads.
During the 19th century, traction engines were found in a number of different industrial applications. They were commonly referred to as road locomotives because of their ability to haul heavy loads along roadways. In many instances, two or more engines were hooked together to provide extra pulling power for extremely heavy loads. These machines were sometimes fitted with a cargo bed similar to a modern-day freight truck. This truck-style version was often referred to as a steam wagon and commonly used in Great Britain until the early 1940s.
Other industrial applications of this engine included road construction and railway equipment. This engine was often designed for use as a steamroller by replacing the standard front wheels with a heavy, single roller. The steamroller version was typically utilized to compact various types of road-paving materials. Some of these engines were fitted with flanged wheels for railway use. These railway versions were typically used for light-duty tasks apart from the main line.
These machines were also used in the agricultural industry to plow and cultivate fields. In firm soil conditions, the plowing implement was attached to the draw-bar and pulled behind the engine. Softer soil required two engines that moved the plow across the field by means of a belt and pulley or cable system. These engines also provided a portable power source for threshing wheat during harvest time. Farmers who did not own a traction engine would typically rent the device from a contractor.
The earliest versions of this device employed a simple chain-drive mechanism extending from the engine to the rear wheels. This was soon replaced by a more efficient gear-driven version. These machines typically featured two large drive wheels in the rear with a pair of smaller wheels at the front for steering purposes. Certain off-road models came equipped with a four-wheel drive mechanism while others featured a type of caterpillar track.
The traction engine was invented in the 1860s by fitting an existing portable steam engine with wheels and a self-propelled drive mechanism. Although portable steam engines had previously been hauled to a worksite by horse, the self-propelled mechanism enabled the machines to be fitted for many new uses. The popularity of these steam-powered engines declined with the increase of gasoline-powered equipment. By the end of the 1920s, steam-powered engines had largely been replaced by more practical, modern equipment.