TRACTION ENGINE

A 'traction engine' (sometimes called a 'road locomotive') is a wheeled steam engine used to move heavy loads, plough ground or to provide power at a chosen location. The name derives from the Latin ''tractus'', meaning 'drawn', since the prime function of any traction engine is to draw a load behind it. They are also known as "road locomotives" to distinguish them from (railway) steam locomotives – that is, steam engines that run on rails.
Traction engines tend to be large, robust and powerful, but extremely heavy, slow, and poorly maneuverable. Nevertheless, they revolutionized agriculture and road haulage at a time when the only alternative prime mover was the draught horse.

The machines typically have two large powered wheels at the back and two smaller wheels for steering at the front. However, some traction engines used a four-wheel-drive variation, and some experimented with a form of caterpillar track.
They became popular in industrialised countries from around 1840, when the farm machinery company Ransomes of Ipswich developed a portable steam engine for agricultural use. Production continued well into the early part of the 20th century.
Traction engines were cumbersome and ill-suited to crossing soft or heavy ground so their agricultural use was usually either "in the belt" – powering farm machinery by means of a continuous leather belt driven by the flywheel – or in pairs, dragging an implement on a cable from one side of a field to another. However, where soil conditions permitted, direct hauling of implements ("off the drawbar") was preferred.
Manufacturers continued to seek a solution to realise the economic benefits of direct-pull ploughing, and, particularly in North America, this led to the development of the steam tractor.

Contents

History

Operation

Usage

Portable engine

Ploughing engine

Agricultural (general purpose) engine

U.S. (agricultural) traction engine

Steam tractor (U.S.)

'Steam tractor (UK)'

Road locomotive

Steamroller

Steam wagon

Steam lorry manufacturers

Steam lorries on film

Terminology

Modern use

Traction engines in popular culture

On film

In fiction

On television

Manufacturers

References

External links

History

Preservation

Research

Further information

See also

Festivals

History

The earliest mobile steam engine is thought to have been invented by Nicolas Cugnot who demonstrated an engine for transporting heavy artillery pieces at the Paris arsenal on October 23, 1769. Unfortunately the idea was discredited when a similar engine ran into a brick wall during a demonstration in Paris.
The traction engine, in the form recognisable today, developed from an experiment in 1859 when Aveling and Porter modified a Clayton & Shuttleworth portable engine, which had to be hauled from job to job by horses, into a self-propelled one. The alteration was made by fitting a long driving chain between the crankshaft and the rear axle, and this set the basic design for the next 60-odd years.
^[1]
All types of traction engines have now been superseded, in commercial use, by internal combustion engine -powered equivalents.

Operation

:''See: steam engine for a description of how the actual engine worked''
Although the first 'traction engine' had a chain drive, it is more typical for large gears to be used to transfer the drive from the crankshaft to the rear axle.
A simple animation showing the steam cycle of a traction engine, the operation of the valve gear and the reversing mechanism, may be found here: ^[2].

Usage

Traction engines saw use in a variety of roles between 1840 and 1940. They can be divided according to their use.

Portable engine

A 'portable engine' is essentially a small ''agricultural engine'' that is not self-propelled. The engine is towed to a work site, by horses or a traction engine, where it can drive machinery using a belt from its flywheel.
The engine may have one or two flywheels mounted on the same crankshaft. Where two are provided, they are of different diameters, mounted either side of the engine. The larger flywheel provides a slower speed for farmyard work (eg chopping feedstuffs) than is required for driving a threshing machine (for example). The crankshaft also drives a boiler feedwater pump which draws water from a barrel placed alongside the engine. Many engines have a simple, but effective, feedwater heater which works by blowing a small portion of the exhaust steam into the water barrel.
The engineering company Clayton & Shuttleworth built hundreds of portable engines, and an example is on display at the Museum of English Rural Life. Many other portable engines have also been preserved, as they were built in large quantities and their relatively small size, compared to a traction engine, makes them a much more viable proposition for restoration by the average enthusiast.

Ploughing engine

A distinct form of traction engine, characterised by the provision of a large diameter winding drum driven by separate gearing from the steam engine. Onto the drum a long length of wire rope was wound, which was used to haul an implement, such as a plough, across a field.
The winding drum was either mounted horizontally (below the boiler), vertically (to one side), or even concentrically, so that it encircled the boiler. The majority were under-slung (horizontal), however, and necessitated the use of an extra-long boiler to allow enough space for the drum to fit between the front and back wheels. These designs were the largest and longest traction engines to be built.
Mostly the ploughing engines worked in pairs, one on each side of the field, with the rope from each machine fastened to the implement to be hauled. The two drivers communicated by signals using the engine whistles.
A variety of implements were constructed for use with ploughing engines. The most common were the 'balance plough' and the 'cultivator' - ploughing and cultivating being the most physically demanding jobs to do on an arable farm. Other implements included the 'mole drainer', used to create an underground drainage 'pipe', and the 'dredger bucket', used for dredging rivers or castle moats.
The engines were frequently provided with a 'spud tray' on the front axle, to store the 'spuds' which would be fitted to the wheels when travelling across claggy ground.
Ploughing engines were rare in the U.S.; ploughs were usually hauled directly by an agricultural engine or steam tractor.

Agricultural (general purpose) engine

The most common form in the countryside. They were used for hauling and as a stationary power source. Even when farmers did not own such a machine they would rely upon it from time to time. Many farms would use draught horses throughout the year, but during the harvest, threshing contractors would travel from farm to farm hauling the threshing machine which would be set up in the field and powered from the engine — a good example of the moveable stationary engine.

U.S. (agricultural) traction engine

Favourable soil conditions meant that U.S. traction engines usually pulled their plows behind them, thereby eliminating the complexities of providing a cable drum and extra gearing, hence simplifying maintenance. American traction engines were manufactured in a variety of sizes, with the 6 horsepower Russell being the smallest commercially made, and the large engines made by Russell, Case, and Reeves being the largest.

Steam tractor (U.S.)

:
In North America, the term ''steam tractor'' usually refers to a type of agricultural tractor powered by a steam engine, used extensively in the late 1800s and early 1900s.

'Steam tractor (UK)'

In Great Britain, the term ''steam tractor'' is more usually applied to the smallest models of traction engine – typically those weighing seven tons or less – used for hauling small loads on public roads. Although known as ''light steam tractors'', these engines are generally just smaller versions of the 'road locomotive'.
They were popular in the timber trade in the UK, although variations were also designed for general light road haulage and showman's use.

Road locomotive

Used for haulage of heavy loads on public highways, it was not uncommon for two or even three to be coupled together to allow heavier loads to be handled.
A particularly distinctive form was the 'Showman's engine'. These were operated by travelling showmen both to tow fairground equipment and to power it when set up; either directly or by running a generator. These could be highly decorated and formed part of the spectacle of the fair. Some were fitted with a small crane that could be used when assembling the ride.

Steamroller

:''Main article: Steamroller''
A distinct form of the steam traction engine, used for road building and flattening ground. Typically designed with a single heavy roller replacing the front wheels and axle, and smooth rear wheels without strakes.
Some traction engines were designed to be 'convertible': the same basic machine could be fitted with either standard ('treaded' or tyred) road wheels, or else smooth rolls – the changeover between the two being achieved in less than half a day.

Steam wagon

These were the earliest steam lorries and came in two basic forms. The earlier ''over-type'' designs resembled traction engines by having a cab built around a horizontal boiler with a round smokebox and chimney (eg Foden). And they resembled lorries in having a load-carrying body and being built around a chassis (so they cannot really be called traction engines).
The more modern ''under-type'' designs have the engine ''under'' the chassis (although the boiler remains in the cab), and generally resemble lorries rather than traction engines.
Early examples of either type had solid tyres, but various developments, including vertical boilers, enclosed cabs and pneumatic tyres were tried by companies such as the Sentinel Waggon Works in a bid to compete with internal combustion engine -powered lorries.

Steam lorry manufacturers

Many traction engine builders also built forms of steam lorry, but some firms specialised in them.
Thornycroft was an established marine engineering company that successfully spawned theSteam Carriage and Wagon Company for the production of steam-powered road vehicles. They supplied steam lorries to the British army, commercial steam waggons and vans, steam cars (for a few years), and buses – London's first powered bus was a Thornycroft double-decker steam bus.
Manufacturers who specialised in the construction of steam lorries include:

★ Foden

★ Mann’s Patent Steam Cart and Wagon Company

★ Sentinel Waggon Works

★ Sheppee – UK company, also built steam cars (briefly)

★ Steam Carriage and Wagon Company (later, Thornycroft), Basingstoke

Steam lorries on film

The 1975 Disney film ''One of Our Dinosaurs is Missing'' featured a steam lorry in a (literally) supporting role. It was used as the 'getaway vehicle' for the theft of a large dinosaur skeleton from the Natural History Museum. It was involved in a lengthy chase sequence through the streets of London – as a result, the steam lorry, and the dinosaur, featured prominently on the film's posters and video/DVD case artwork.
The lorry was based on an 'unusual' prototype, a long wheelbase undertype, with a small vertical boiler mounted to one side of the cab, and no windscreen.

Terminology

★ 'spud' or 'lug' – strip of angled metal that could be bolted to the driving wheels to provide greater traction on soft or heavy ground. Spuds were often required on ploughing engines when moving across farmland.

★ 'strake' – name for the diagonal bars cast into the wheel rims to provide traction on unmade ground (similar to the tread on a pneumatic tyre).

Modern use

Although no longer used commercially, traction engines of all types continue to be maintained and preserved by enthusiastic individuals and are frequently exhibited at agricultural shows in Europe (particularly the UK), Canada and the United States. They are often a main attraction in a live steam festival.

Traction engines in popular culture

On film

:''See also: Steam rollers on film

★ The 1962 film The Iron Maiden featured a showman's engine as the film's star, along with many others, at the annual rally at Woburn Abbey.

In fiction

:''See also: Steam rollers in fiction

★ 'Trevor the Traction Engine' is one of the non-railway characters featured in The Railway Series of children's books by the Rev. W. Awdry. Appearing in several of the books, the traction engine was originally 'saved from scrap' by The Vicar of Wellsworth with the help of Edward the Blue Engine. Trevor has also appeared in a number of episodes in the TV spin-off Thomas the Tank Engine and Friends.

★ In the book '''Gumdrop and The Farmer's Friend''', by Val Biro, the vintage motor-car Gumdrop is rescued from a snowy ditch by "The Farmer's Friend", a traction engine belonging to a local farmer. Some months later, the two vehicles are instrumental in thwarting a pair of car thieves.
The end-papers of the book include a simplified cut-away drawing of the traction engine: a single-cylinder, 6 NHP Fowler light tractor, built in 1903.

On television

★ Fred Dibnah of Bolton, England was known as a National Institution for the conservation of old traction engines in Great Britain. His television series, Fred Dibnah's Made in Britain, shows him touring the United Kingdom in his rebuilt, 10 ton traction engine.

Manufacturers

:''See List of traction engine manufacturers''

References

1. Discovering Traction Engines, , Harold, Bonnett, Shire Publications Ltd, ,
2. Animation (Flash) showing the steam cycle and reversing mechanism of a traction engine
    – ''NB contains embedded music, which can be turned off!'' (Accessed 23 Apr 2007)

External links

History

★ History of mechanisation in farming – ''Timeline, 1700 - 1914 (MERL)''

★ Concise history of the traction engine – ''evolution, from earliest experiments to widespread manufacture, plus definitions of the six main types''

★ Social Impact of Road Haulage – ''Timeline including early development history of steam-powered road vehicles (from Hampshire County Council Museum Service)''

★ History of Waterloo Gasoline Traction Engine Company (Iowa) – ''the first gasoline-powered traction engine, and forerunner of the John Deere tractor range''

★ "Steam Dinosaur" – world's oldest surviving traction engine ''(plus lots of history of early Aveling products)''

Preservation

★ UK Traction engine rallies

★ East Anglian Traction Engine Society

★ Western Minnesota Steam Threshers Reunion

★ Engine Resources

★ National Traction Engine Trust

Research

★ Database of historical agricultural engineering companies of the UK – ''(MERL)''

★ Steam Traction magazine – searchable article archive (1951-date)
   ''Covers mainly-US traction engines and steam tractors, threshing machines and steam-powered agricultural machinery.''

★ Steam Scenes – extensive 'searchable' photo library – ''preserved traction engines in the UK, Europe, Australia and New Zealand''

★ Steam-Up – photo library – ''UK-based preserved traction engines''

★ Traction Time – searchable photo library & discussion forums – ''Information about UK-based preserved traction engines''

Further information

★ Interactive diagram of a traction engine showing major components.

★ Glossary of traction engine terminology

See also

★ Live steam

★ Steam tractor

★ Museum of English Rural Life (MERL) – ''UK national collection of history of farming''

Festivals

★ Great Dorset Steam Fair

★ Fort Edmonton

★ Steam Era, a festival in Milton, Ontario, Canada

★ Rough and Tumble Engineers Historical Association, Kinzers, Penn. See http://www.roughandtumble.org.

★ Ontario Agricultural Museum

★ Austin, Manitoba Museum http://www.ag-museum.mb.ca/