Stephenson’s Rocket/ Rainhill Trials

Sans Pereil

Sans Pereil

Stephenson’s locomotive “Rocket” won the Rainhill Trials On 8 October 1829 . Stephenson’s Rocket was an early steam locomotive of 0-2-2 wheel arrangement, built in 1829 at the Forth Street Works of Robert Stephenson and Company in Newcastle Upon Tyne, specially for the Rainhill Trials held by the Liverpool & Manchester Railway in 1829 to choose the best design to power the railway. Though the Rocket was not the first steam locomotive, it brought together several innovations to produce the most advanced locomotive of its day and became the template for most steam engines in the following 150 years. It had a tall smokestack chimney at the front, a cylindrical boiler in the middle, and a separate firebox at the rear. The large front pair of wooden wheels was driven by two external cylinders set at an angle. The smaller rear wheels were not coupled to the driving wheels, giving an 0-2-2 wheel arrangement. As the first railway intended for passengers more than freight, the rules emphasised speed and would require reliability, but the weight of the locomotive was also tightly restricted. Six-wheeled locomotives were limited to six tons, four-wheeled locomotives to four and a half tons. In particular, the weight of the train expected to be hauled was to be no more than three times the actual weight of the locomotive.

Stephenson realised that whatever the size of previously successful locomotives, this new contest would favour a fast, light locomotive of only moderate hauling power. His most visible decision was to use a single pair of driving wheels, with a small carrying axle behind giving a 0-2-2 arrangement. The use of single drivers gave several advantages. The weight of coupling rods was avoided and the second axle could be smaller and lightweight, as it only carried a small proportion of the weight. Rocket placed 2½ tons of its 4¼ ton total weight onto its driving wheels,a higher axle load than the rival locomotive Sans Pareil, even though the 0-4-0 was heavier overall at 5 ton, and officially disqualified by being over the 4½ ton limit.  Stephenson’s past experience convinced him that the adhesion of the locomotive’s driving wheels would not be a problem, particularly with the light trains of the trials contest. Rocket uses a multi-tubular boiler design. Previous locomotive boilers consisted of a single pipe surrounded by water. Rocket has 25 copper fire-tubes that carry the hot exhaust gas from the firebox, through the wet boiler to the blast pipe and chimney. This arrangement resulted in a greatly increased surface contact area of hot pipe with boiler water when compared to a single large flue. Additionally, radiant heating from the enlarged separate firebox helped deliver a further increase in steaming and hence boiler efficiency.The advantages of the multiple-tube boiler were quickly recognised, even for heavy, slow freight locomotives. By 1830, Stephenson’s past employee Timothy Hackworth had re-designed his return-flued Royal George as the return-tubed Wilberforce class.

Rocket also used a blastpipe, feeding the exhaust steam from the cylinders into the base of the chimney so as to induce a partial vacuum and pull air through the fire. .the blastpipe worked well on the multi-tube boiler of Rocket but on earlier designs with a single flue through the boiler it had created so much suction that it tended to rip the top off the fire and throw burning cinders out of the chimney, vastly increasing the fuel consumption. Like the Lancashire Witch, Rocket had two cylinders set at angle from the horizontal, with the pistons driving a pair of 4 ft 8.5 in (1.435 m) diameter wheels. Most previous designs had the cylinders positioned vertically, which gave the engines an uneven swaying motion as they progressed along the track. Subsequently Rocket was modified so that the cylinders were set close to horizontal, a layout that influenced nearly all designs that followed. The cylinders were also connected directly to the driving wheels, an arrangement which is found in all subsequent steam locomotives.The firebox was separate from the boiler and was double walled, with a water jacket between them. This firebox was heated by radiant heat from the glowing coke, not just convection from the hot exhaust gas.Locomotives of Rocket’s era were fired by coke rather than coal. Local landowners were already familiar with the dark clouds of smoke from coal-fired stationary engines and had imposed regulations on most new railways that locomotives would ‘consume their own smoke’. The smoke from a burning coke fire was much cleaner than that from coal. It was not until thirty years later and the development of the long firebox and brick arch that locomotives would be effectively able to burn coal directly.Rocket’s first firebox was of copper sheet and of a somewhat triangular shape from the side. The throatplate was of firebrick, possibly the backhead too.

When the Liverpool and Manchester Railway was approaching completion, the directors of the railway ran a competition to decide whether stationary steam engines or locomotives would be used to pull the trains. So the Rainhill Trials were run in October 1829 in Rainhill,Lancashire (now Merseyside) they featured several tests for each locomotive which were performed over the course of several days.The Rainhill stretch of the Railway was very level for a mile or so: a perfect site for the Trials .. The Rainhill Trials were arranged as an open contest that would let them see all the locomotive candidates in action, with the choice to follow. Regardless of whether or not locomotives were settled upon, a prize of £500 was offered to the winner of the trials. Three notable figures from the early days of engineering were selected as judges: John Urpeth Rastrick, a locomotive engineer of Stourbridge, Nicholas Wood, a mining engineer from Killingworth with considerable locomotive design experience and John Kennedy, a Manchester cotton spinner and a major proponent of the railway Locomotives were run two or three per day, and several tests for each locomotive were performed over the course of several days.The Rainhill stretch of the Railway was very level for a mile or so: a perfect site for the Trials.

The locomotive Cycloped was the first to drop out of the competition. Built with “legacy technology”, it used a horse walking on a drive belt for power, and was withdrawn after an accident caused the horse to burst through the floor of the engine.Next to retire was Perseverance. Damaged en route to the competition, Burstall spent five days repairing it. When it failed to reach the required 10 miles per hour (16 km/h) on its first tests the next day, it was withdrawn from the trial. It was granted a £26 consolation prize.Sans Pareil nearly completed the trials, though at first there was some doubt as to whether it would be allowed to compete as it was 300 pounds (140 kg) overweight. However, it did eventually complete eight trips before cracking a cylinder. Despite the failure it was purchased by the Liverpool & Manchester, where it served for two years before being leased to theBolton and Leigh Railway.The last engine to take part was Novelty. In complete contrast to Cycloped it was cutting-edge for 1829, lighter and considerably faster than the other locomotives in the competition. It was accordingly the crowd favourite. Reaching a then-astonishing 28 miles per hour (45 km/h) on the first day of competition, it later suffered some damage to a boiler pipe which could not be fixed properly on site in the time allotted. Nevertheless it continued its run on the next day, but upon reaching 15 mph the pipe gave way again and damaged the engine severely enough that it had to drop out.So, the Rocket was the only locomotive to complete the trials. It averaged 12 miles per hour (19 km/h) (achieving a top speed of 30 miles per hour (48 km/h)) hauling 13 tons, and was declared the winner of the £500 prize. The Stephensons were accordingly given the contract to produce locomotives for the Liverpool & Manchester Railway.

In 1980 the Rocket 150 celebration was held to mark the 150th Anniversary of the trials. A replica of Novelty was built for the event, which was also attended by replicas of Sans Pareil and Rocket (plus coach).The Rocket replica bent its axle in Bold Colliery railway sidings during the event and was exhibited on a low loader carriage.The event was also attended by:Lion, at the time of Rocket 150 the oldest operable steam locomotive in existence. Flying Scotsman No. 4472, LMS 4-6-0 Jubilee class No. 5690 Leander, Sir Nigel Gresley No. 4498, GWR 0-6-0 No. 3205, lMS Class 4 MT 2-6-0 No 43106, BR 92220 Evening Star, the last steam locomotive to be built by British Railways,LMS 4-6-2 Princess Elizabeth No. 6201,  Class 86 locomotives 86214, Sans Pareil and 86235. In a recent (2002) restaging of the Rainhill Trials using replica engines, neither Sans Pareil nor Novelty completed the course. In calculating the speeds and fuel efficiencies, it was found that Rocket would still have won, as its relatively modern technology made it a much more reliable locomotive than the others. Novelty almost matched it in terms of efficiency, but its firebox design caused it to gradually slow to a halt due to a build up of molten ash (called “clinker”) cutting off the air supply. The restaged trials were run over a section of line in Llangollen, Wales, and were the subject of a BBC Timewatch documentary.

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