Unusual Traction Engines

Gallery opened: 20 Aug 2012

Updated 12 Mar 2013

Two Box-patent engines added
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The steam traction engine was for a long time a vital means of freight transport, and for providing power on the spot for ploughing, threshing, funfairs, and so on. They were the mainstay of agriculture from the end of the mid 1800's to the 1930s ,when they were replaced by the early petrol tractors. Until heavy lorries appeared they were the only way to move items that were too large to go by rail, such as ship boilers. You can good a idea of how conventional traction engines looked on Wikipedia.

However, as in most forms of engineering endeavour, there some unconventional designs of varying merit; some were ingenious, some less than inspired. You can see some of them here.

TRACTION ENGINE BASICS
The power of traction engines was measured in peculiar units called "Nominal Horse Power. This was calculated solely from the piston area, ignoring the piston stroke and the steam pressure. It therefore only had a very tenuous connection with any measure of real power, but nevertheless seems to have somehow persisted to the end of the traction engine era. NHP are quoted here but treat then with the greatest of caution.

Traction engines had either a 3-shaft or a 4-shaft transmission system. The 3 shafts were the crankshaft, the counter shaft and the rear axle itself. 4-shaft designs had an extra countershaft; they were generally thought to be less durable.


UNUSUAL DRIVE METHODS
The majority of traction engines transmitted their power to the rear wheels by spur gearing, via 3 or 4 shafts, as explained above. A problem with this was that it required a fixed rear axle with no suspension movement, in order to keep the final pair of gears in proper mesh.

Various methods were used to address this problem.

Left: An engine built by Fowell to Box's patent: 1877

This engine, of 8 nominal horse-power, implemented the final stage of drive through coupling rods, rather like a steam locomotive. This allowed vertical motion of the sprung rear wheels. The lower countershaft ran underneath the boiler to drive the rear wheel on the other side via another crank and coupling rod, presumably set at 90 degrees to avoid dead-centre problems. This arrangement was patented by William Box in 1876. Note the front steering position. The middle counter-shaft has two sets of teeth to allow changing gear.

This engine (numbered Fowell No 2) was delivered to William Box in May 1877 and seems to have been entirely successful. In the first two years of its life it covered 3000 miles hauling loads of 15 to 25 tons, and after 20 years it run over 30,000 miles.

Note also that Fowell is NOT a misprint for Fowler. Fowell was a quite different company manufacturing traction engines. Fowell built a second Box patent engine (No 18) that was delivered in July 1882, and a third (No 30) was delivered in May 1884. A fourth (No 41) was delivered in 1888, and that was Fowell's last of this type.

However, another source (The Big Box) states that Fowell built five of these engines

Left: The second Fowell Box-patent engine, No 18: 1882

The engine belonged to The Market Lavington Brick and Pottery Works, owned by Holloway Brothers. Concern over the breakage of bricks due to the rough haulage by a traction engine with no rear suspension was the original impetus to develop the Box patent.

This engine ran over and kllled its original purchaser, William Box senior, in 1894.

The steersman here is one Charlie Sheppard. There is a band-brake on the drive wheel of the lower countershaft.

Left: The fourth Fowell Box-patent engine, No 41: 1888

Of 8 nominal horse-power. It looks essentially identical to No 18 above.

No photograph has so far been traced of the third Fowell Box-patent engine, No 30, but it is known it was called "Lion".

Left: A drawing of the Box patent engine built by Robey: 1879

The Robey company also built a Box patent engine in 1879.

The design is rather more conventional than the Fowell version. Here the rear axle is behind the firebox instead of in front of it, and there is a conventional steering position at the rear. Once again the middle counter-shaft has two sets of teeth to allow changing gear.

There is a band-brake on the drive wheel of the lower countershaft, controlled by a handwheel visible below the cylinder.

Another source (The Big Box) states that Robey built two of these engines


THREE-WHEELED TRACTION ENGINES
Virtually all traction engines had four wheels, but some had three. This usually turned out to be a bad idea.

Left: A 3-wheeled Fowler traction engine

It is not known why Fowler, a respected British builder, started producing 3-wheeled traction engines in 1871. Four engines were shown at the Royal Agricultural Show, Wolverhampton, in that year; two of 6 and two of 12 NHP. A steam dome was placed on top of the steam-jacketed cylinder. All were 3-shaft engines. They had enveloping side skirts, not for safety, but so that the sight of moving gears would not frighten horses. For the same reason the flywheel spokes were covered with a plate to make the rotation less obvious.

The 3-wheelers were claimed to turn more easily and run more quietly. However, they ran into trouble on country roads as the central front wheel tended to run sideways off the central raised bit of road between the wheel ruts. They were also inclined to rear up when pulling heavy loads, as there was less weight at the front than on a conventional four-wheeled engine.


UNUSUAL METHODS OF TRACTION

Above: The Steeplechaser with 12-foot rear wheels. The pipe running forward goes to the blastpipe in the base of the chimney

This extraordinary machine was built by Fowler in 1877. The 12-foot (3.66m) wheels were intended to reduce the ground pressure and give better propulsion in soft soil. Twin cylinders were mounted over the firebox; the forward crankshaft drove a countershaft running across the boiler through a 2-speed gear and differential. Pinions at each end of this countershaft engaged with a circular rack bolted inside the rim of each rear wheel; this can be clearly seen in the photograph. The rear weight was not carried on the rear axle, but, via leaf springs, on a lower shaft with a double flanged wheel at each end. These ran on a circular track on the insde of the wheel rims.

Not surprisingly, this machine proved too clumsy to be useful, but that did not stop Fowlers from producing a similar machine two years later with 9-foot (2.7m) driving wheels. The usual maximum diameter was 7-foot.

Left: Fowler compound engine fitted with experimental Botrail tracks

This engine started life in 1912 as a standard Fowler Class R3 road locomotive, but early the following year was fitted with the Botrail arrangement of steel shoes held on by steel cables.

The photograph shows trials on Redcar Sands on 22nd April 1913. Two heavily laden trucks were towed.

The Botrail was invented by Frank Bottrill, engineer, of 41 Moubray Street, Albert Park, State of Victoria, Australia. He was issued with British Patent 8844 (in 1912) for "Improvements relating to Ped-rail Shoes for Heavy Road Vehicles".

Left: The Botrail wheel, taken from patent 8844.

Each of the 8 shoes has two steel cables attached at each end.

Left: Another photograph of the experimental Botrail engine at Redcar Sands

Left: A demonstration of the Pedrail wheels

The pedrail wheel was invented in 1903 by Bramah Joseph Diplock, of London. Like the Botrail it was intended to allow traction engines to move over difficult terrain. It consisted of circular rubber-shod "feet" attached to the wheel by ball-and-socket joints and sliding spokes. A system of springs and levers inside the wheel kept the appropriate feet in contact with the ground. There is more info on Wikipedia.

The Pedrail concept was abandoned when it became clear that caterpillar tracks were a more durable way of moving over rough ground.


TRACTION ENGINES WITH CATERPILLAR TRACKS
Caterpillar tracks were sometimes fitted to traction engines, and proved more effective than the foot-wheel arrangements shown in the previous section. These were the seeds and weak beginnings of the WW1 tank. The history in this section has now been sorted out.

Left: Hornsby tracked vehicle driven by paraffin engine: 1905

A chain-track was added to a paraffin-engined tractor by the chief engineer of Hornsby, David Roberts, and was patented in July 1904. In 1905 Roberts demonstrated this tractor unofficially to the British Army's Mechanical Transport Committee. A formal demonstration was staged at Grantham in February 1906. The idea was to use it for gun haulage, rather than as a prototype tank, but the Royal Artillery was unenthusiastic.
Three oil-powered engines for gun haulage were made, plus the steam crawler displayed below. One oil crawler survives in working condition at the Bovington Tank Museum.

Note the very steam-type chimney, to carry the exhaust away from the crew. No doubt this was a spare part from a steam traction engine. The Wikipedia entry on the Richard Hornsby company identifies it as a steam tractor, which seems to be incorrect. There is no sign of a boiler. The vehicle is clearly moving, as shown by the blurred spokes of the flywheel, but there is not a trace of steam visible anywhere.

While this machine is often credited with being influential in the development of the tank, serious study of the possibilities of tracked tanks did not begin in Britain until 1914.

Counter-intuitively, the Hornsby steam tractor was built after the paraffin-powered versions, in 1910.

Left: The Hornsby steam crawler: 1910

This machine was shipped to Canada from England in 1910, being sold to the Northern Light Power & Coal Company for use hauling coal to the Klondike gold fields in the Yukon, where it worked until 1927. This was the only sale, and the Hornsby company became disillusioned with their "chain track"and sold the patent rights to the Holt Manufacturing Company in 1914.

Left: The Hornsby steam crawler: 1910

Sadly only the tracks of the steam crawler survive. They can be seen on this very fine website dedicated to the Hornsby steam crawler.

Above: A model of the Hornsby tracked traction engine

This fantastic piece of work is is a model of the Hornsby engine built to 4-inch scale. I assume this means 4 inches to the foot, ie one-third scale. Pictured here at the Lincoln (England) steam fair in 2008. You can see this wonderful thing in action on YouTube. It is owned by Steve Baldock.

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