The last steam locomotive to be built by British Railways: Standard Class 9F 2-10-0 no. 92220 Evening Star
(preserved as part of the National Collection)
Drawing of a Great Western Railway King class locomotive

Steam locomotives dominated rail traction from the mid 19th century until the mid 20th century, after which they were superseded by diesel and electric locomotives. A Diesel locomotive is a type of Railroad Locomotive in which the prime mover is a Diesel engine. "Electric Trains" redirects here For the 1995 Squeeze single see Electric Trains (song.

Origins

Trevithick's locomotive, 1804 the first successful steam locomotive
Stephenson's Rocket 1829, the winner of the Rainhill Trials

The earliest railways employed horses to draw carts along railed tracks. See also Rail transport The history of rail transport dates back nearly 500 years and includes systems with man or horse power and rails of wood or stone

As the development of steam engines progressed through the 1700s, various attempts were made to apply them to road and railway use. A steam engine is a Heat engine that performs Mechanical work using Steam as its Working fluid. [1] The first attempts were made in Great Britain; the earliest steam rail locomotive was built in 1804 by Richard Trevithick and Andrew Vivian. See also Kingdom of Great Britain Great Britain (Breatainn Mhòr Prydain Fawr Breten Veur Graet Breetain is the larger of the two main islands Richard Trevithick ( April 13, 1771 &ndash April 22, 1833) was a British Trevithicks Dampfwagenjpg|thumb|right|The London Steam Carriage by Trevithick and Vivian demonstrated in London in 1803 It ran with mixed success on the narrow gauge "Penydarren tramroad" at Merthyr Tydfil in Wales. A narrow gauge railway (or narrow gauge railroad) is a Railway that has a Track gauge narrower than the of Standard gauge railways Penydarren was the fourth of the great Ironworks established at Merthyr Tydfil in South Wales. Merthyr Tydfil today Government The current Borough boundaries date back to 1974 when the former county borough of Merthyr Tydfil expanded slightly to cover [1]. Then followed the successful twin cylinder locomotive by Christopher Blackett's team built at Wylam in 1811, closely followed by Matthew Murrays' rack locomotive for the edge railed Middleton Railway in 1812 [2]. Wylam (ˈwɪləm is a small village approximately 10 miles (16 kilometers west of Newcastle upon Tyne. Matthew Murray (1765 &mdash 20 February 1826) was a Steam engine and Machine tool manufacturer who designed and built the first commercially Wagonways are the horses equipment and tracks used for hauling wagons which preceded steam powered railways There are two styles of waggonway and two spellings The Middleton Steam Railway is the world's oldest continuously working railway These early efforts culminated in 1829 with the Rainhill Trials and the opening of the Liverpool and Manchester Railway a year later making exclusive use of steam power for both passenger and freight trains. The Rainhill Trials were an important competition in the early days of steam locomotive railways run in October of 1829 in Rainhill, Merseyside (between Liverpool The Liverpool and Manchester Railway (L&MR was the world's first inter-city passenger Railway in which all the trains were timetabled and were hauled for most of the distance

Basic form

Scheme of steam locomotive. (see Steam locomotive components)

Boiler

The typical steam locomotive employs a horizontal fire-tube boiler partially filled with water. A listing of the components typically found on Steam locomotives Guide to steam locomotive components (The image is of a composite imaginary locomotive not all components A fire-tube boiler is a type of boiler in which hot gases from the fire pass through one or more tubes within the boiler A firebox, its walls and roof constantly surrounded by water, is incorporated generally to the rear of the boiler when the locomotive is travelling chimney-first; this is where a combustible is burnt, the heat generated thereby being transferred to the water in the boiler in order to make the steam that constitutes working medium. A boiler or steam generator is a device used to create Steam by applying Heat energy to Water. The combustion gases flow from the firebox into a bundle of parallel tubes, also surrounded by water, which continue to transfer heat to the water. At the front of the boiler is the smokebox, a chamber where the combustion gases are mixed with the jet of exhaust steam, the whole being ejected into a chimney (US: "smoke stack") voiding into the outside air. A smokebox is one of the major basic parts of a steam Locomotive.

Steam circuit

The generated steam is stored in the steam space above the water in the partially-filled boiler. Its working pressure is limited by spring-loaded safety valves. It is then collected either in a perforated tube fitted above the water level or from a dome that often houses the regulator valve, or throttle, the purpose of which is to control the amount of steam leaving the boiler. The steam then either travels directly along and down a steam pipe to the engine unit or may have first to pass into the wet header of a superheater, the role of the latter being to eliminate water droplets suspended in the "saturated steam", the state in which it leaves the boiler. See Superheating for the physics process A superheater is a device in a Steam engine that heats the steam generated by the On leaving the superheater, the "dried" steam exits the dry header of the superheater and passing down a steam pipe enters the steam chests adjacent to the cylinders of a reciprocating engine. Inside each steam chest is a sliding valve that distributes the steam via ports that connect the steam chest to the ends of the cylinder space. The role of the valves is twofold: admission of each fresh dose of steam and exhaust of the used steam once it has done its work.

The cylinders are double acting, with steam admitted to each side of the piston in turn. In a two-cylinder locomotive, one cylinder is located on each side of the locomotive. The cranks are set 90° out of phase with each other. During a full rotation of the driving wheel, steam provides four power strokes per revolution; that is to say each cylinder receives two injections of steam. The first stroke is to the front of the piston and the second stroke to the rear of the piston; hence two working strokes. Consequently two deliveries of steam onto each piston face in two cylinders generates a full revolution of the driving wheel. The driving wheels are connected on each side by coupling rods (US: "connecting rods") to transmit power from the main driver to the other wheels. A coupling rod or side rod connects the Driving wheels of a Locomotive. At the two "dead centres", when the connecting rod is on the same axis as the crankpin on the driving wheel, it will be noted that no turning force can be applied. In a Reciprocating engine, the dead center is the position of a piston in which it is farthest from or nearest to the Crankshaft. If the locomotive were to come to rest in this position it would be impossible for it to move off again, so the cylinders and crankpins are arranged such that the dead centres occur out of phase with each other. This precaution is unnecessary on most other reciprocating engines (such as an internal combustion engine) which are never expected to start from rest under their own power, and employ a flywheel to overcome the dead centres.

Walschaerts valve gear in a steam locomotive. The Walschaerts valve gear is a type of Steam engine Valve gear invented by Belgian railway mechanical engineer Egide Walschaerts In this animation, the red colour represents live steam entering the cylinder, blue represents expanded (spent) steam being exhausted from the cylinder. The bouncing ball animation (below consists of these 6 frames Live steam is Steam under pressure obtained by heating water in a Boiler. Note that the cylinder receives two steam injections during each full rotation; the same occurs in the cylinder on the other side of the engine.

Exhaust steam is directed upwards to the atmosphere through the chimney, by way of a nozzle called a blastpipe that gives rise to the familiar "chuffing" sound of the steam locomotive. The blastpipe is part of a Steam Locomotive that discharges exhaust steam from the cylinders into the Smokebox beneath the Chimney The blastpipe is placed at a strategic point inside the smokebox that is at the same time traversed by the combustion gases drawn through the boiler and grate by the action of the blast. The combining of the two streams is crucial to the efficiency of any steam locomotive and the internal profiles of the chimney, (or more strictly speaking, the ejector) require careful design and adjustment. This has been the object of intensive studies by a number engineers (and almost totally ignored by others with sometimes catastrophic effect). The fact that the draught depends on the exhaust pressure means that power delivery and power generation are automatically self-adjusting and among other issues, a balance has to be struck between obtaining sufficient draught for combustion whilst giving the gases and particles sufficient time to be consumed. In the past, fierce draught could lift the fire off the grate, or cause the ejecting of unburnt particles leading to the dirt and pollution for which steam locomotives had an unenviable reputation in the past. Moreover, the pumping action of the exhaust has the counter effect of exerting back pressure on the side of the piston receiving steam, thus somewhat reducing cylinder power. Designing the exhaust ejector has become a specific science in which Chapelon, Giesel and Porta were successive masters, and was largely responsible for spectacular improvements in thermal efficiency but drastic reduction in maintenance time[4] and pollution. André Chapelon (26 October 1892 – 22 July 1978 was a noted French Mechanical engineer and designer of advanced Steam locomotives Engineer of Ecole Centrale

Chassis

With European locomotives, the chassis is the principle structure onto which the boiler is mounted and which incorporates the various elements of the running gear. The chassis consists of two mainframes kept apart and square by spacers and “buffer beams”. For many years, in America practice , the boiler was the main structural element, with built-up bar frames, ‘’smokebox saddle/cylinder’’ structure and drag beam integrated therein; but from the late 1920s with the introduction of ‘’superpower’’, the ‘’cast-steel locomotive bed’’ became the norm, incorporating frames, spring hangers, motion brackets, smokebox saddle and cylinder blocks incorporated into a single complex, sturdy but heavy casting. André Chapelon developed a similar welded structure with around 30% saving in weight for the still-born 2-10-4 locomotives the construction of which was begun then abandoned in 1946.

Running gear

This includes the brake gear, wheel sets, axleboxes, springing and the "motion" that includes connecting rods and valve gear. The transmission of the power from the pistons to the rails and the behaviour of the locomotive as a vehicle, able to negotiate curves, points and irregularities in the track are issues of paramount importance. Because reciprocating power has to be directly applied to the rail from 0 rpm upwards, this poses unique problems of ‘’adhesion’’ of the driving wheels to the smooth rail surface. Adhesive weight is the portion of the locomotive’s weight bearing on the driving wheels. This is made more effective if a pair of driving wheels is able to make the most of its ‘’axle load’’ i. e. its individual share of the adhesive weight. Locomotives with ‘’compensating levers’’ connecting the ends of plate springs have often been deemed a complication but locomotives fitted with them have usually been less prone to loss of traction due to wheel-slip.

Locomotives with total adhesion, i. e. where all the wheels are coupled together, generally lack stability at speed. This makes desirable the inclusion of unpowered carrying wheels mounted on two-wheeled trucks or 4-wheeled bogies centred by springs that help to guide the locomotive through curves. These usually take the weight of the cylinders in front or of the firebox at the rear end when the width of this exceeds that of the mainframes. For multiple coupled wheels on a rigid chassis a variety of systems for controlled side-play exist.

Fuel and water

Water gauge. Here the water in the boiler is at the “top nut”, the maximum working level.

Generally, the largest locomotives are permanently coupled to a tender that carries the water and fuel. Alternatively, locomotives working shorter distances carry the fuel in a bunker, and the water in tanks mounted on the engine, the latter placed either alongside the boiler or on top of it; these are called tank engines. A tank locomotive is a Steam locomotive that carries its own fuel and water on it instead of pulling it behind it in a tender.

The fuel source used depends on what is economically available locally to the railway. In the UK and parts of Europe, a plentiful supply of coal made this the obvious choice from the earliest days of the steam engine. German, Russian, Australian and British railways experimented using coal dust to fire locomotives. Coal dust is a fine powdered form of Coal, which is created by the crushing grinding or pulverizing of coal Up to around 1850 in the U. S. A the vast majority of locomotives burnt wood until most of the Eastern forests were cleared; from that time on coal burning became more widespread and wood burners were restricted to rural and logging districts. In Europe, this lasted well into the 20th century. Bagasse, a waste by-product of the refining process, was burned in sugar cane farming operations. Bagasse (sometimes spelled bagass) is the Biomass remaining after Sugarcane or Sorghum stalks are crushed to extract their juice and is Sugarcane ( Saccharum) is a genus of 6 to 37 species (depending on taxonomic interpretation of tall perennial grasses (family Poaceae tribe Andropogoneae In the USA, the ready availability of oil made this a popular steam locomotive fuel; the Southern Pacific, for example, went directly from wood to oil. equipment. In Victoria, Australia after World War II, many steam locomotives were converted to heavy oil firing. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including

A number of tourist lines and heritage locomotives in Switzerland, Argentina and Australia have been using light diesel-type oil. [5].

Water was supplied at stopping places and locomotive depots from a dedicated water tower connected to water cranes or gantries. A water tower, watershed, or elevated water tower is a large elevated water storage container A water crane is a device used for delivering a large volume of Water into the tank or tender of a Steam locomotive. In the UK, the USA and France, water troughs (US track pans) were provided on some main lines to allow locomotives to replenish their water supply without stopping. A track pan ( American terminology or water trough ( British terminology is a device to enable a steam railway locomotive to replenish its water supply This was achieved by using a 'water scoop' fitted under the tender or the rear water tank in the case of a large tank engine; the fireman remotely lowered the scoop into the trough, the speed of the engine forced the water up into the tank, and the scoop was raised again once it was full.

Water is an essential element in the operation of a steam locomotive; because as Swengel argued:

it has the highest specific heat of any common substance; that is more thermal energy is stored by heating water to a given temperature than would be stored by heating an equal mass of steel or copper to the same temperature. In addition, the property of vapourising (forming steam) stores additional energy without increasing the temperature. . . water is a very satisfactory medium for converting thermal energy of fuel into mechanical energy

Swengel went on to note that "at low temperature and relatively low boiler outputs" good water and regular boiler washout was an acceptable practise, even though such maintenance was high. As steam pressures increased, however, a problem of "foaming" or "priming" developed in the boiler, wherein dissolved solids in the water formed "tough-skinned bubbles" inside the boiler, which in turn were carried into the steam pipes and could blow off the cylinder heads. To overcome the problem, hot mineral concentrated water was deliberately wasted (blowing down) from the boiler from time to time. Higher steam pressures required more blowing down of water out of the boiler. Oxygen generated by boiling water attacks the boiler and with increased steam pressures the rate of rust (iron oxide) generated inside the boiler increases. One way to help overcome the problem was water treatment. Swengel suggested that the problems around water, contributed to the interest in electrification of railways. [6]

In the 1970s L.D. Porta developed a sophisticated heavy duty chemical water treatment that not only keeps the inside of the boiler clean and prevents corrosion, but modifies the foam in such a way as to form a compact "blanket" on the water surface that filters the steam as it is produced, keeping it pure and preventing carry-over into the cylinders of water and suspended abrasive matter. Livio Dante Porta ( March 21 1922 - June 10 2003) was an Argentine steam locomotive engineer

Crew

A locomotive is controlled from the backhead of the firebox and the crew is usually protected by a cab. A crew of at least two people is normally required to operate a steam locomotive. One, the driver (US: engineer), is responsible for controlling the locomotive and the fireman is responsible for the fire, steam pressure, and water. A railroad engineer, railway engineer, locomotive engineer, train operator, train driver or engine driver is a person who operates

Fittings and appliances

Further information: Category:locomotive parts

All locomotives are fitted with a variety of appliances. Some of these relate directly to the operation of the steam engine; while others are for signalling, train control, or other purposes. In the United States the Federal Railroad Administration mandated the use of certain appliances over the years in response to safety issues. The Federal Railroad Administration (FRA is an administration in the United States Department of Transportation. The most typical appliances are as follows:

Steam pumps and injectors

Water must be forced into the boiler, to replace that which is exhausted after delivering a working stroke to the pistons. Early engines used pumps driven by the motion of the pistons. Later steam injectors replaced the pump, while some engines use turbopumps. An injector, ejector, steam ejector or steam injector is a pump-like device that uses the Venturi effect of a converging-diverging As the name suggests a turbopump comprises basically two main components a rotodynamic Pump and a driving Turbine, both mounted on the same shaft Standard practice evolved to use two independent systems for feeding water to the boiler. Vertical glass tubes, known as water gauges or water glasses, show the level of water in the boiler. A sight glass or water gauge is a transparent tube through which the operator of a tank or Boiler can observe the level of liquid contained within

Boiler lagging

Manometer-type pressure gauge mounted alongside the chimney of a replica of Stephenson's Rocket

Large amounts of heat are wasted if a boiler is not insulated. Many techniques have been developed for the measurement of Pressure and Vacuum. Replica Rocket and coachjpg|thumb|right|A replica coach and Rocket at the Rocket 150 event]] Stephenson's Rocket was an early Steam locomotive of 0-2-2 Early locomotives used shaped wooden battens fitted lengthways along the boiler barrel and held in place by metal bands. Improved insulating methods included: applying a thick paste containing a porous mineral, such as kieselgur or shaped blocks of insulating compound such as magnesia blocks[7] were attached. Diatomaceous earth (ˌdaɪətəˈmeɪʃəs ˈɝθ also known as DE, TSS, diatomite, diahydro, kieselguhr, kieselgur and In the latter days of steam, "mattresses" of stitched asbestos cloth were fixed stuffed with asbestos fibre (but on separators so as not quite to touch the boiler); however in most countries, asbestos is nowadays banned for health reasons. Asbestos is a group of Minerals with long thin fibrous Crystals The word "asbestos" (῾ἀσβεστος is derived from a Greek adjective The most common modern day material is glass wool, or wrappings of aluminium foil. Glass wool is a form of Fibreglass where very thin strands of Glass are arranged into a spongy texture similar to Steel wool.

The lagging is protected by a close fitted sheet-metal casing[8] known as boiler clothing or cleading.

Effective lagging is particularly important for fireless locomotives; however in recent times under the influence of L. A fireless locomotive was a type of Locomotive designed for use under conditions restricted by either the presence of flammable material (such as in mines or the need D. Porta, "exaggerated" insulation has been practised for all types of locomotive on all surfaces liable to dissipate heat, such as cylinder ends and facings between the cylinders and the mainframes. This considerably reduces engine warmup time with marked increase in overall efficiency.

Safety valves

Early locomotives were fitted with a valve controlled by a weight suspended from the end of a lever, the steam outlet being stopped by a cone-shaped valve. As there was nothing to prevent the weighted lever from bouncing when the locomotive ran over irregularities in the track, thus wasting steam, the weight was replaced by a more stable spring loaded column, often supplied by Salter, a well-known spring scale manufacturer. A spring scale is a Weighing scale used to measure Force, such as the force of Gravity, exerted on a Mass or the force of a person's grip The danger of all these devices was that the driving crew could be tempted to add weight to the arm in order to increase pressure; most boilers were therefore from early times fitted with a tamper-proof "lockup" direct-loaded ball valve protected by a cowl. In the late 1850s, John Ramsbottom introduced an ingenious safety valve that became very popular in Britain during the latter part of the 19th Century. John Ramsbottom may refer to John Ramsbottom (engineer (1814&ndash1897 an English mechanical engineer who created many inventions for railways Not only was this valve tamper-proof, but any intervention on the part of the driver could only have the effect of easing pressure. Richardson's "pop" valve was an American invention introduced in 1867[9] and was so designed as to release the steam only at the moment when the pressure attained the maximum permitted. This type of valve is in almost universal use at present. The British Great Western Railway was a notable exception to this rule retaining the direct loaded type until the end of its separate existence because it was considered that such a valve lost less pressure between opening and closing. The Great Western Railway ( GWR) was a British railway company and a notable example of Civil engineering, linking London with the West

Pressure gauge

Pressure gauges on Blackmore Vale. The SR West Country and Battle of Britain Classes, also known as Light Pacifics or Spam Cans, are classes of air-smoothed 4-6-2 ''Pacific'' The right-hand one shows boiler pressure, the one on the left steam chest pressure

The earliest locomotives did not show the pressure of steam in the boiler, but it was possible to estimate this by the position of the safety valve arm which often extended onto the firebox back plate; gradations marked on the spring column gave a rough indication of the actual pressure. The promoters of the Rainhill trials urged that each contender have a proper mechanism for reading the boiler pressure and Stephenson devised a nine-foot vertical tube of mercury with a sight-glass at the top, mounted alongside the chimney, for the Rocket. The Rainhill Trials were an important competition in the early days of steam locomotive railways run in October of 1829 in Rainhill, Merseyside (between Liverpool George Stephenson ( 9 June 1781 &ndash 12 August 1848) was an English Civil engineer and mechanical engineer Replica Rocket and coachjpg|thumb|right|A replica coach and Rocket at the Rocket 150 event]] Stephenson's Rocket was an early Steam locomotive of 0-2-2 The Bourdon tube gauge, in which the pressure straightens an oval-section, coiled tube of brass or bronze connected to a pointer, was introduced in 1849 and quickly gained acceptance. Many techniques have been developed for the measurement of Pressure and Vacuum. This is the device used today. [10] Some locomotives have an additional pressure gauge in the steam chest. This helps the driver avoid wheel-slip at startup, by warning if the regulator opening is too great.

Spark arrestor and self cleaning smokebox

Typical self-cleaning smokebox design

Wood-burners emit large quantities of flying sparks which necessitate an efficient spark arresting device generally mostly housed in the smokestack. Many types were fitted[11], the most common early type being the Bonnet stack that incorporated a cone-shaped deflector placed before the mouth of the chimney pipe plus a wire screen covering the wide stack exit; more efficient was the Radley and Hunter centrifugal type patented in 1850, (generally known as the diamond stack) incorporating baffles so orientated as to induce a swirl effect in the chamber that encouraged the embers to burn out and fall to the bottom as ash. In the self-cleaning smokebox the opposite effect was achieved: by allowing the flue gasses to strike a series of deflector plates, angled in such a way that the blast was not impaired, the larger particles were broken into small pieces that would be ejected with the blast, rather than settle in the bottom of the smokebox to be removed by hand at the end of the run. As with the arrestor, a screen was incorporated to retain any large embers. [12]

Locomotives of the British Railways standard classes fitted with self-cleaning smokeboxes were identified by a small cast oval plate marked "S. British Railways (BR built 2537 steam locomotives in the period 1948–1960 1538 to pre-nationalisation designs and 999 to its own standard designs C. ", fitted at the bottom of the smokebox door. These engines required different disposal procedures and the 'S. C. ' plate highlighted this need to depot staff.

Stokers

A factor that limits locomotive performance is the rate at which fuel is fed into the fire. In the early 20th century some locomotives became so large, that the fireman could not shovel coal fast enough. [8] In the United States, various steam-powered mechanical stokers became standard equipment and were adopted and used elsewhere including Australia and South Africa.

Feedwater heating

Introducing cold water into a boiler reduces power, and from the 1920s a variety of heaters were incorporated. A feedwater heater is a Power plant component used to pre-heat water delivered to a Steam generating Boiler. The most common type for locomotives was the exhaust steam feedwater heater that piped some of the exhaust through small tanks mounted on top of the boiler or smokebox or else into the tender tank; the warm water then had to be delivered to the boiler by a small auxiliary steam pump. The rare economiser type differed in that it extracted residual heat from the exhaust gases. An example of this is the pre-heater drum(s) found on the Franco-Crosti boiler. The Franco-Crosti boiler is a type of Boiler used for Steam locomotives.

The use of live steam and exhaust steam injectors also assists in the pre-heating of boiler feed water to a small degree, though there is no efficiency advantage to live steam injectors. Such pre-heating also reduces the thermal shock that a boiler might experience when cold water is introduced directly. This is further helped by the top feed where water is introduced to the highest part of the boiler and made to trickle over a series of trays. G.J. Churchward fitted this arrangement to the high end of his domeless coned boilers Other British lines such as the LBSCR fitted a few locomotives with the top feed inside a separate dome forward of the main one. George Jackson Churchward CBE ( 31 January 1857 - 19 December 1933) was Chief mechanical engineer of the Great Western The London Brighton and South Coast Railway (LB&SCR (commonly known as "the Brighton line" was a Railway company in the United Kingdom from 1846 to 1923

Condensers and water re-supply

The conventional means of watering a locomotive was by refilling its tender or tank, from trackside water towers or standpipes.

Steam locomotives consume vast quantities of water, and supplying this was a constant logistical problem. In some desert areas, condensing engines were devised. These engines had huge radiators in their tenders and instead of exhausting steam out of the funnel it was captured and passed back to the tender and condensed. The cylinder lubricating oil was removed from the exhausted steam to avoid a phenomenon known as priming, a condition caused by foaming in the boiler which would allow water to be carried into the cylinders causing damage because of its incompressibility. The most notable engines employing condensers (Class 25C) worked across the Karoo desert of South Africa, from the 1950 until the 1980s. The Karoo (a Khoisan word of uncertain etymology) is a semi- Desert region of South Africa.

Some British and American locomotives were equipped with scoops which collected water from "water troughs" (US: "track pans") while in motion, thus avoiding stops for water. A track pan ( American terminology or water trough ( British terminology is a device to enable a steam railway locomotive to replenish its water supply In the US, small communities often did not have refilling facilities. During the early days of railroading, the crew simply stopped next to a stream and filled the tender using leather buckets. This was known as “jerking water” and led to the term "jerkwater towns" (meaning a small town, a term which today is considered derisive). [13] In Australia and South Africa, locomotives in drier regions operated with large oversized tenders and some even had an additional water wagon, sometimes called a "canteen" or in Australia (particularly in New South Wales) a "water gin".

Steam locomotives working on underground railways (such as London's Metropolitan Railway) were fitted with condensing apparatus for a different, but obvious, reason. The Metropolitan Railway (MetR and the Metropolitan District Railway (District were the first two underground railways to be built in London, creating the world's A steam locomotive condensing apparatus differs in purpose from the usual closed cycle Steam engine condenser, in that its function is primarily either to recover These were still being used between King's Cross and Moorgate into the early 1960s. King's Cross station is a major railway terminus opened in 1852 Moorgate station is a London Underground and National Rail station in the City of London, on Moorgate, north of London Wall.

Braking

Locomotives have their own braking system, independent from the rest of the train. Locomotive brakes employ large shoes which press against the driving wheel treads. With the advent of air brakes, a separate system also allowed the driver to control the brakes on all cars. An air brake is a conveyance braking system applied by means of compressed air. These systems require steam-powered pumps, which are mounted on the side of the boiler or on the smokebox front. Such systems operated in the United States, Canada and Australia.

An alternative to the air brake is the vacuum brake. Where vacuum brakes are used, a steam-operated ejector is mounted on the engine instead of the air pump. The vacuum brake is a braking system used on Trains It was first introduced in the mid 1860s and a variant the automatic vacuum brake system became almost An aspirator, also called an Eductor-jet pump or filter pump is a device that produces Vacuum by means of the Venturi effect. A secondary ejector or crosshead vacuum pump is used to maintain the vacuum in the system. Vacuum systems existed on British, Indian and South African rail networks.

Steam locomotives are nearly always fitted with sandboxes from which sand can be delivered to the rails to improve traction and braking in wet weather. Traction refers to the Friction between a drive member and the surface it moves upon where the friction is used to provide motion On American locomotives the sandboxes, or sand domes, are usually mounted on top of the boiler. In Britain, the limited loading gauge precludes this, so the sandboxes are mounted just above, or just below, the running plate. A loading gauge is the envelope or contoured shape within which all Railroad cars, Locomotives coaches Buses Trucks and other

Lubrication

“Wakefield” brand displacement lubricator mounted on a locomotive boiler backplate. Through the right-hand sight glass a drip of oil (travelling upwards through water) can be seen.

The pistons and valves on the earliest locomotives were lubricated by the enginemen dropping a lump of tallow down the blast pipe. Lubrication is the process or technique employed to reduce wear of one or both surfaces in close proximity and moving relative to each another by interposing a substance called Tallow is a rendered form of Beef or Mutton Fat, processed from Suet. The blastpipe is part of a Steam Locomotive that discharges exhaust steam from the cylinders into the Smokebox beneath the Chimney [14]

As speeds and distances increased, mechanisms were developed that injected thick mineral oil into the steam supply. The first, a displacement lubricator, mounted in the cab, uses a controlled stream of steam condensing into a sealed container of oil. The displacement lubricator is an automatic oil lubricator for Steam engines first introduced in the United Kingdom in 1860 by John Ramsbottom Water from the condensed steam displaces the oil into pipes. The apparatus is usually fitted with sight-glasses to confirm the rate of supply. A later method uses a mechanical pump worked from one of the crossheads. A crosshead (or crosshead bearing) is a Bearing used in large Reciprocating engines whether Internal combustion engines or Steam engines In both cases, the supply of oil is proportional to the speed of the locomotive.

Big-end bearing (with connecting rod and coupling rod) of Blackmoor Vale showing pierced cork stoppers to oil reservoirs. In a reciprocating Piston engine, the connecting rod or conrod connects the Piston to the crank or Crankshaft. A coupling rod or side rod connects the Driving wheels of a Locomotive. The SR West Country and Battle of Britain Classes, also known as Light Pacifics or Spam Cans, are classes of air-smoothed 4-6-2 ''Pacific''

Lubricating the frame components (axle bearings, horn blocks and bogie pivots) depends on capillary action: trimmings of worsted yarn are trailed from oil reservoirs into pipes leading to the respective component. 0-9 Note for 4-4-0 2-6-4T 0-4-4-0 etc See Whyte notation or UIC classification A B A bogie (ˈboʊgi (BŌ-gē is a Wheeled wagon or trolley In mechanics terms a bogie is a Chassis or framework carrying wheels attached to a vehicle Capillary action, capillarity, capillary motion, or wicking is the ability of a substance to draw another substance into it Worsted (pronunciation) is the name of a Yarn, the Cloth made from this yarn and a yarn weight category [12] The rate of oil supplied is controlled by the size of the bundle of yarn and not the speed of the locomotive, so it is necessary to remove the trimmings (which are mounted on wire) when stationary. However, at regular stops (such as a terminating station platform) oil finding its way onto the track can still be a problem.

Crank pin and crosshead bearings carry small cup-shaped reservoirs for oil. These have feed pipes to the bearing surface that start above the normal fill level, or are kept closed by a loose-fitting pin, so that only when the locomotive is in motion does oil enter. In United Kingdom practice the cups are closed with simple corks, but these have a piece of porous cane pushed through them to admit air. It is customary for a small capsule of pungent oil (aniseed or garlic) to be incorporated in the bearing metal to warn if the lubrication fails and excess heating or wear occurs.

Buffers

In British practice, the locomotive usually had buffers at each end to absorb compressive loads ("buffets"[15]). A buffer is a part of the buffers-and-chain coupling system used on the Railway systems of many countries among them most of those in Europe, for attaching The tensional load of drawing the train (draft force) is carried by the coupling system. A coupling (or a coupler) is a mechanism for connecting Rolling stock in a train Together these control slack between the locomotive and train, absorb minor impacts, and provide a bearing point for pushing movements.

In American practice all of the forces between the locomotive and cars are handled through the coupler and its associated draft gear, which allows some limited slack movement. A coupling (or a coupler) is a mechanism for connecting Rolling stock in a train Small dimples called "poling pockets" at the front and rear corners of the locomotive allowed cars to be pushed on an adjacent track using a pole braced between the locomotive and the cars.

Pilots

In the United States, South Africa and Australia, locomotives had a pilot at the front end. In Railroading the pilot is the device mounted at the front of a locomotive to deflect obstacles from the track that might otherwise derail the train Plow-shaped, and called cow catchers, they were quite large and were designed to remove obstacles from the track such as cattle, bison, other animals or tree limbs. In Railroading the pilot is the device mounted at the front of a locomotive to deflect obstacles from the track that might otherwise derail the train Though unable to "catch" stray cattle these distinctive items remained on locomotives in those countries until the end of steam. Switching engines usually replaced the pilot with small steps. In places like Victoria, Australia, the cow catchers became a trade mark of that state's engines (Dee:1998).

Preserved GWR locomotive Bradley Manor, until recently still used on Britain's national rail network. The Great Western Railway ( GWR) was a British railway company and a notable example of Civil engineering, linking London with the West Between the two oil lamps signifying an express passenger service a high-intensity electric lamp has been added to comply with modern safety standards

When night operations began, railway companies in some countries equipped their locomotives with lights to allow the driver to see what lay ahead of the train or to enable others to see the locomotive. Originally headlights were oil or acetylene lamps, but when electric lights became available in the late 1880s, they quickly replaced the older types. Acetylene ( IUPAC name ethyne), C2H2 is a Hydrocarbon belonging to the group of Alkynes It is the simplest of all alkynes

Britain used low intensity oil lamps and were not intended to allow the driver to see the way ahead (locomotive drivers were expected to have sufficient route knowledge) but were used to indicate the class of a train by their position on the front of the locomotive. Four lamp irons were provided: one below the chimney and three evenly spaced across the top of the buffer beam. The exception to this was the Southern Railway and its constituents, who added two lamp irons one each side of the smokebox, and the arrangement of lamps (or in daylight white circular plates) told railway staff the origin and destination of the train.

In some countries heritage steam operation continues on the national network. Some railway authorities have mandated powerful headlights on at all times, including during daylight. This was to further inform the public or track workers of any active trains.

Bells and whistles

Main article: Train whistle

Locomotives used bells and steam whistles from earliest days. A train whistle or air whistle, (originally referred to as a steam trumpet) is an audible signaling device on a Steam locomotive used to warn that the In the United States and Canada bells warned of a train in motion. In Britain, where all lines are by law fenced throughout,[16] bells were only a requirement on railways running on a road (i. e. not fenced off), for example a tramway along the side of the road or in a dockyard. Consequently only a minority of locomotives in the UK carried bells. Whistles are used to signal personnel and give warnings. Depending on the terrain the locomotive was being used in the whistle could be designed for long distance warning of impending arrival, or more for localised use.

Early bells and whistles were sounded through pull-string cords and levers. As the steam era approached the 1950s, automatic air-operated bells were made use of on locomotives such as the Challenger (steam locomotive) and Big Boy. Big Boy was the name given to the Union Pacific Railroad 's twenty-five 4000 class 4-8-8-4 Mallet articulated Steam locomotives

Automatic Train Control

From early in the twentieth century operating companies in such countries as Germany and Britain began to fit locomotives with in-cab signalling which automatically applied the brakes when a signal was passed at "caution". The Automatic Warning System (AWS is a form of limited Cab signalling and Train protection system introduced in 1956 in the United Kingdom to help In Britain these became mandatory in 1956.

Booster engines

In the United States and Australia the trailing truck was often equipped with an auxiliary steam engine which provided extra power for starting. This booster engine was set to cut out automatically at a certain speed. A booster engine for Steam locomotives is a small two-cylinder steam Engine back-gear-connected to the trailing truck axle on the locomotive or if none the lead truck On the narrow gauged New Zealand railway system, six Kb 4-8-4 locomotives had boosters; the only 3 ft 6 in (metre gauge) engines in the world to have such equipment.

Variations

Numerous variations to the simple locomotive occurred as railways attempted to develop more powerful, more efficient and fast steam locomotives.

Cylinders

Some locomotives received extra cylinders and experiments combined two locomotives in one (e. g. the Mallet and Garratt locomotives). The Mallet Locomotive is a type of Articulated locomotive, invented by a Swiss engineer named Anatole Mallet Some locomotives carried their cylinders vertically alongside the boiler and drove the wheels through a system of shafts and gears (e. g. the Shay locomotive; see "geared steam locomotive"). Shay locomotive was the most widely used Geared steam locomotive. A geared steam locomotive is a type of Steam locomotive which uses reduction gearing in the drivetrain as opposed to the common directly-driven design

From about 1930, most new British express passenger locomotives were 4-6-0 or 4-6-2 types with three or four cylinders. Examples include:

Cab forward

In the United States on the Southern Pacific Railroad a series of cab forward locomotives had the cab and the firebox at the front of the locomotive and the tender behind the smokebox, so that the engine appeared to run backwards. The GWR 4073 Class or Castle class locomotives were a group of 4-6-0 Steam locomotives of the Great Western Railway. Disambiguation LNER Thompson Class A1/1, LNER Peppercorn Class A1 The London and North Eastern Railway LNER The term cab forward refers to various rail and Road Vehicle designs which place the driver's compartment substantially farther towards the front than This was only possible by using oil-firing. Southern Pacific selected this design to provide smoke-free breathing for the locomotive's engineer as they went through the SP's numerous mountain tunnels and snow sheds. Another variation was the Camelback locomotive with the cab half-way along the boiler. A camelback locomotive is a type of Steam locomotive with the driving cab placed in the middle astride the boiler

Steam turbines

Steam turbines were one of the experiments in improving the operation and efficiency of steam locomotives. Experiments with steam turbines using direct-drive and electrical transmissions, in different countries, proved mostly unsuccessful. A steam turbine locomotive is a Steam locomotive which transmits steam power to the wheels via a Steam turbine. [8] The LMS also built Turbomotive, a largely successful attempt to prove the efficiency of steam turbines. London Midland for the new (2007 railway company The London Midland and Scottish Railway ( LMS) was a British Railway company The Turbomotive was a modified Princess Royal Class Steam locomotive designed by William Stanier and built by the London Midland and Scottish Railway [8] Had it not been for the outbreak of WW2, more may have been built. The Turbomotive ran from 1935-49, when it was rebuilt into a conventional locomotive because replacement of many parts was required, an uneconomical proposition for a 'one-off' locomotive. In the United States the Union Pacific, Chesapeake and Ohio, and Norfolk & Western railways all built turbine-electric locomotives. The Chesapeake and Ohio Railway (C&O was a Class I railroad formed in 1869 in Virginia from many smaller railroads begun in the 19th century The Norfolk and Western Railway ( N&W), a US Class I railroad, was formed by more than 200 railroad mergers between 1838 and 1982 The Pennsylvania Railroad (PRR) also built turbine locos but with a direct-drive gearbox. The Pennsylvania Railroad was an American Railroad, founded in 1846 However, all designs failed due to dust, vibration, design flaws, or inefficiency below speed. The last one in service was the N&W's being retired in January 1958.

Valve gear

Numerous technological advances improved the steam engine. Early locomotives used simple valve gear that gave full power in either forward or reverse. [10] Soon Stephenson valve gear allowed the driver to control cutoff; this was largely superseded by Walschaerts valve gear and similar patterns. The Stephenson valve gear or Stephenson link or shifting link is a simple design of Valve gear that was widely used throughout the world for all kinds of The Walschaerts valve gear is a type of Steam engine Valve gear invented by Belgian railway mechanical engineer Egide Walschaerts Early locomotive designs using slide valves and outside admission were easy to construct, but inefficient and prone to wear. The D Slide Valve was a form of Rectilinear slide valve for use in rotative Steam engines invented by William Murdoch and patented in 1799. [10] Eventually, slide valves were superseded by inside admission piston valves, though there were attempts to apply poppet valves (common by then on stationary engines) in the 20th century. A piston valve is a device used to control the motion of a Fluid along a tube or pipe by means of the Linear motion of a Piston within A poppet valve is a Valve consisting of a hole usually round or oval and a tapered plug usually a disk shape on the end of a shaft also called a valve stem Stephenson valve gear was generally placed within the frame and was difficult to access for maintenance; later patterns applied outside the frame, were readily visible and maintained.

Compounding

From 1876, compound locomotives came on the scene, which used the engine's steam twice. A compound engine unit is a type of Steam engine where steam is expanded in two phases There were many compound locomotives especially where long periods of continuous efforts were needed. Compounding was an essential ingredient of the quantum leap in power achieved by André Chapelon's rebuilds from 1929. André Chapelon (26 October 1892 – 22 July 1978 was a noted French Mechanical engineer and designer of advanced Steam locomotives Engineer of Ecole Centrale A common application was to articulated locomotive, the most common being that of Anatole Mallet in which the high pressure stage was attached directly to the boiler frame; in front of this was pivoted a low pressure engine on its own frame, taking the exhaust from the rear engine. Biarr-Bay-lokjpg|thumb|250px|Early Mallet 2-cylinder compound locomotive working the Bayonne-Anglet-Biarritz (B [17]

Articulated and Duplex types

Articulation itself proved very popular, and there were numerous variations, both compound and simple. Articulated locomotive usually means a Steam locomotive with one or more engine units which can move relative to the main frame Duplex locomotives with two engines in one rigid frame were also tried, but were not notably successful. A duplex locomotive is a Steam locomotive that divides the driving force on its wheels by using two pairs of cylinders rigidly mounted to a single Locomotive frame For example, the Pennsylvania Railroad's 4-4-4-4 T1 class, designed for very fast running, suffered incurable slippage problems throughout their careers. The Pennsylvania Railroad was an American Railroad, founded in 1846 [18]

Hybrid power

Mixed power locomotives, utilising steam and diesel propulsion, have been produced in Russia, Britain and Italy. A steam and diesel hybrid locomotive was a railway locomotive with a piston engine which could run on either steam from a boiler or diesel fuel.

Manufacture

United States

Steam locomotives required regular service and overhaul (often at government-regulated intervals). Many alterations occurred during overhauls. New appliances were added, unsatisfactory features removed, cylinders improved or replaced. Any part of the locomotive, including boilers were replaced or upgraded. On the Baltimore and Ohio Railroad two 2-10-2 locomotives were dismantled; the boilers were placed onto two new Class T 4-8-2 locomotives and the residue wheel machinery made a pair of Class U 0-10-0 switchers with new boilers. The Baltimore and Ohio Railroad ( B&O) was one of the Oldest railroads in the United States and the first Common carrier railroad A 2-10-2 Steam locomotive in the Whyte notation for Wheel arrangements has two Leading wheels (one axle ten Driving wheels (five driven Under the Whyte notation for the classification of Steam locomotives a 4-8-2 Locomotive has four Leading wheels (generally arranged in a Union Pacific's fleet of 3 cylinder 4-10-2 engines were converted into two cylinder engines in 1942, because of high maintenance problems. Under the Whyte notation for the classification of Steam locomotives, a 4-10-2 Locomotive has four Leading wheels ten Driving wheels

Great Western Railway No. The Great Western Railway ( GWR) was a British railway company and a notable example of Civil engineering, linking London with the West 6833 Calcot Grange, a 4-6-0 Grange class steam locomotive, at Bristol Temple Meads station, Bristol, England. In the Whyte notation, a 4-6-0 is a Railroad Steam locomotive that has a two-axle Leading truck followed by three Driving axles The Great Western Railway (GWR 6800 Class or Grange Class was a mixed traffic class of steam locomotive Bristol Temple Meads railway station is the oldest and largest Railway station in Bristol, England Note the Belpaire (square-topped) firebox. The Belpaire firebox is a type of firebox used on Steam locomotives It was invented by Alfred Belpaire of Belgium.

United Kingdom

Before the 1923 Grouping, the picture in the UK was mixed. Grouping is form of hierarchical knowledge representation similar to mind mapping, concept mapping and argument mapping, all of which need to observe The larger railway companies built locomotives in their own workshops but the smaller ones and industrial concerns ordered them from outside builders. A large market for outside builders was abroad because of the home-build policy exercised by the main railway companies.

Between 1923 and 1947, the "Big Four" railway companies (the Great Western Railway, the London, Midland and Scottish Railway, the London and North Eastern Railway and the Southern Railway) all built most of their own locomotives. The Great Western Railway ( GWR) was a British railway company and a notable example of Civil engineering, linking London with the West London Midland for the new (2007 railway company The London Midland and Scottish Railway ( LMS) was a British Railway company The The Southern Railway (SR was a British railway company established in the 1923 Grouping. Generally speaking, they only bought locomotives from outside builders when their own works were fully occupied (or as a result of government-mandated standardisation during wartime).

From 1948, British Railways allowed the former "Big Four" companies (now designated "Regions") to continue to build their own designs, but also created a range of "standard" locomotives which supposedly combined the best features from each region. See also Rail transport in Great Britain, National Rail, Network Rail This article is about the defunct entity "British Railways" Although a policy of "dieselisation" was adopted in 1955, BR continued to build new steam locomotives until 1960 (the last being named Evening Star). British Railways Standard Class 9F number 92220 Evening Star, is a preserved British steam locomotive

Some independent manufacturers produced steam locomotives for a few more years, the last British-built industrial steam locomotive being constructed by Hunslet in 1971. The Hunslet Engine Company is a British Locomotive -building company founded in 1864 at Jack Lane Hunslet, Leeds, West Yorkshire, Since then, a few specialised manufacturers have continued to produce small locomotives for narrow gauge and miniature railways, but as the prime market for these is the tourist and heritage railway sector, the demand for such locomotives is limited. A heritage railway ( United Kingdom) preserved railway ( United Kingdom) or tourist railroad ( United States and Canada) is a

Australia

In Australia, Clyde Engineering of Sydney and also the Eveleigh Workshops built steam locomotives for the New South Wales Government Railways. For a topic outline on this subject see List of basic Australia topics. Downer EDI Rail ( EDi Rail until 2 July 2007) is a rail company based in Australia. Sydney (ˈsɪdniː is the most populous city in Australia, with a Metropolitan area population of approximately 4 Eveleigh is an inner-city Suburb of Sydney, in the state of New South Wales, Australia. The New South Wales Government Railways (NSWGR was the government department that operated the New South Wales Government's railways until the establishment of the Public Transport These include the C38 class 4-6-2, the first five were build at Clyde with streamlining, the other 25 locomotives were built at Eveleigh (13) in Sydney, and Cardiff Workshops (12) near Newcastle. A streamliner is any vehicle that incorporates streamlining to produce a shape that provides less resistance to air. In Queensland, steam locomotives were locally constructed by Walkers. Similarly the South Australian state government railways also manufactured steam locomotives locally at Islington in Adelaide. The Victorian Railways constructed most of their locomotives at their Newport Workshops and Bendigo while in the early days locomotives were built in Ballarat. See also Rail transport in Victoria The Victorian Railways operated railways in the Australian state of Victoria from 1859 to 1983 Bendigo is a regional city in central Victoria Australia, located in the City of Greater Bendigo. Ballarat (formerly spelt "Ballaarat" is a city in Victoria, Australia, and one of the country's largest inland cities Locomotives constructed at the Newport shops ranged from the nA class 2-6-2T built for the narrow gauge, up to the H class 4-8-4, the largest conventional locomotive ever to operate in Australia, which weighed 260 tons. Under the Whyte notation for the classification of Steam locomotives by Wheel arrangement, a 2-6-2 has two Leading wheels six coupled The former Victorian Railways, the state railway authority in Victoria, Australia built a number of experimental Narrow gauge railway lines around However, the title of largest locomotive in Australia goes to the 263 ton NSWGR AD60 class 4-8-4+4-8-4 Garratt (Oberg:1975), which were built by Beyer-Peacock in the United Kingdom. A 4-8-4+4-8-4, in the Whyte notation for the classification of Steam locomotives by Wheel arrangement, is a Garratt Articulated locomotive Beyer Peacock and Company was an English Railway Locomotive manufacturer with a Factory in Gorton, Manchester

Categorisation

The Gov. Stanford, a 4-4-0 (in Whyte notation) locomotive typical of 19th century American practice

Steam locomotives are categorised by their wheel arrangement. A 4-4-0 is a type of Steam locomotive. In the Whyte notation, 4-4-0 signifies that it has a two-axle Bogie ( Am The Whyte notation for classifying Steam locomotives by Wheel arrangement was devised by Frederick Methvan Whyte Other classification schemes like The two dominant systems for this are the Whyte notation and UIC classification. The Whyte notation for classifying Steam locomotives by Wheel arrangement was devised by Frederick Methvan Whyte Other classification schemes like The UIC classification is a comprehensive system for describing the Wheel arrangement of Locomotives Multiple units and Trams It is

The Whyte notation, used in most English speaking and Commonwealth countries, represents each set of wheels with a number. Different arrangements were given names which usually reflect the first usage of the arrangement; for instance the "Santa Fe" type (2-10-2) is so called because the first examples were built for the Atchison, Topeka and Santa Fe Railroad. A 2-10-2 Steam locomotive in the Whyte notation for Wheel arrangements has two Leading wheels (one axle ten Driving wheels (five driven The Atchison Topeka and Santa Fe Railway, often abbreviated as Santa Fe, was one of the larger railroads in the United States. These names were informally given and varied according to region and even politics.

The UIC classification is used mostly in European countries apart from the United Kingdom. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located It designates consecutive pairs of wheels (informally "axles") with a number for non-driving wheels and a capital letter for driving wheels (A=1, B=2 etc). So a Whyte 4-6-2 designation would be an equivalent to a 2-C-1 UIC designation.

On many railroads, locomotives were organised into classes. Class (locomotive refers to a group of locomotives built to a common design for a single railroad These broadly represented locomotives which could be substituted for each other in service, but most commonly a class represented a single design. As a rule classes were assigned some sort of code, generally based on the wheel arrangement. Classes also commonly acquired nicknames representing notable (and sometimes uncomplimentary) features of the locomotives.

Performance

Measurement

In the steam locomotive era, two measures of locomotive performance were generally applied. At first, locomotives were rated by tractive effort This can be roughly calculated by multiplying the total piston area by 85% of the boiler pressure (a rule of thumb reflecting the slightly lower pressure in the steam chest above the cylinder) and dividing by the ratio of the driver diameter over the piston stroke. Tractive Effort (abbr TE is the pulling force exerted normally by a Locomotive, though the term could also be used for anything else that pulls a load However, the precise formula is:

Tractive Effort is defined as the average force developed during one revolution of the driving wheels at the rail head. [6] This is expressed as:

$t = \frac {cPd^2s} {D}$.

where d is bore of cylinder (diameter) in inches, s is cylinder stroke, in inches, P is boiler pressure in pound per square inch, D is driving wheel diameter in inches, c is the effective cutoff. In a Steam engine, cutoff is the point in the Piston stroke at which the inlet valve is closed [20]

It is critical to appreciate the use of the term 'average', as not all effort is constant during the one revolution of the drivers for at some points of the cycle only one piston is exerting turning moment and at other points both pistons are working. Not all boilers deliver full power at starting and also the tractive effort decreases as the rotating speed increases. [6]

Tractive effort is a measure of the heaviest load a locomotive can start or haul at very low speed over the ruling grade in a given territory. [6]

However, as the pressure grew to run faster freight and heavier passenger trains, tractive effort was seen to be an inadequate measure of performance because it did not take into account speed.

Therefore in the 20th century, locomotives began to be rated by power output. A variety of calculations and formulas were applied, but in general railroads used dynamometer cars to measure tractive force at speed in actual road testing. A dynamometer car is a Railroad Maintenance of way car used for measuring various aspects of a Locomotive 's performance This measure was termed drawbar horsepower in the United States and remained the standard measure of performance to the end of mainline usage.

British railway companies have been reluctant to disclose figures for drawbar horsepower and have usually relied on continuous tractive effort instead. The continuous tractive effort is the highest force that a vehicle can exert over an extended period of time

Relation to wheel arrangement

Whyte classification is connected to locomotive performance, but through a somewhat circuitous path. Given adequate proportions of the rest of the locomotive, power output is determined by the size of the fire, and for a bituminous coal-fuelled locomotive, this is determined by the grate area. Modern non-compound locomotives are typically able to produce about 40 drawbar horsepower per square foot of grate. Tractive force, as noted earlier, is largely determined by the boiler pressure, the cylinder proportions, and the size of the driving wheels. However, it is also limited by the weight on the driving wheels (termed adhesive weight), which needs to be at least four times the tractive effort. [8]

The weight of the locomotive is roughly proportional to the power output; the number of axles required is determined by this weight divided by the axleload limit for the trackage where the locomotive is to be used. The number of driving wheels is derived from the adhesive weight in the same manner, leaving the remaining axles to be accounted for by the leading and trailing bogies. [8] Passenger locomotives conventionally had two-axle leading bogies for better guidance at speed; on the other hand, the vast increase in the size of the grate and firebox in the 20th century meant that a trailing bogie was called upon to provide support. On the European continent, some use was made of several variants of the "Bissel-bogie" in which the swivelling movement of a single axle truck controls the lateral displacement of the front driving axle (and in one case the second axle too). This was mostly applied to 8-coupled express and mixed traffic locomotives and considerably improved their ability to negotiate curves whilst restricting overall locomotive wheelbase and maximising adhesion weight.

As a rule, "shunting engines" (US "switching engines") omitted leading and trailing bogies, both to maximise tractive effort available and to reduce wheelbase. Speed was unimportant; making the smallest engine (and therefore smallest fuel consumption) for the tractive effort paramount. Driving wheels were small and usually supported the firebox as well as the main section of the boiler. Banking engines (US "helper engines") tended to follow the principles of shunting engines, except that the wheelbase limitation did not apply, so banking engines tended to have more driving wheels. A bank engine ( United Kingdom / Australia) (colloquially a banker) or helper engine or pusher engine ( North America) In the US, this process eventually resulted in the Mallet type with its many driven wheels, and these tended to acquire leading and then trailing bogies as guidance of the engine became more of an issue. The Mallet Locomotive is a type of Articulated locomotive, invented by a Swiss engineer named Anatole Mallet

As locomotive types began to diverge in the late 1800s, freight engine designs at first emphasised tractive effort, whereas those for passenger engines emphasised speed. Over time, freight locomotive size increased, and the overall number of axles increased accordingly; the leading bogie was usually a single axle, but a trailing truck was added to larger locomotives to support a larger firebox that could no longer fit between or above the driving wheels. Passenger locomotives had leading bogies with two axles, fewer driving axles, and very large driving wheels in order to limit the speed at which the reciprocating parts had to move.

The end of steam in general use

The introduction of electric locomotives at the turn of the 20th century spelled the beginning of the end for steam locomotives, although that end was long in coming. "Electric Trains" redirects here For the 1995 Squeeze single see Electric Trains (song. As Diesel power, more especially with electric transmission, became more reliable in the 1930s it gained a foothold in North America [22]. The full changeover took place there during the 1950s. In continental Europe large-scale electrification had displaced steam power by the 1970s, Steam had in its favour familiar technology and adapted well to local facilities and consume a wide variety of fuels; this led to its continued use in many countries to the end of the 20th Century. They have considerably less thermal efficiency than modern diesels, requiring constant maintenance and labour to keep them operational. Water is required at many points throughout a rail network and becomes a major problem in desert areas, as are found in some regions within the United States, Australia and South Africa. In other localities the local water is unsuitable. The reciprocating mechanism on the driving wheels of a two-cylinder single expansion steam locomotive tended to pound the rails (see "hammer blow"), thus requiring more maintenance. Hammer blow, in Rail terminology, refers to the vertical Forces transferred to the track by the Driving wheels of a Steam locomotive MOW redirects here For other meanings see MOW (disambiguation. Raising steam from coal was a matter of hours steam raising which brought serious pollution problems; coal-burning around depots; coal burning locomotives required fire cleaning and ash removal between turns of duty. This was all done in the open air by hand in deplorable working conditions. Diesel or electric locomotives, by comparison, drew benefit from new custom built servicing facilities. Finally, the smoke from steam locomotives was deemed objectionable; in fact, the first electric and diesel locomotives were developed to meet smoke abatement requirements[23] although this did not take into account the high level of invisible pollution in diesel exhaust smoke especially when idling. It should also be remembered that the power for most electric trains is, in fact, derived from steam, generated in a power station.

United States

Northwestern Steel and Wire locomotive number 80, July 1964

United Kingdom

Trials of diesel locomotives and railcars began in the United Kingdom in the 1930s but made only limited progress. A railcar (not to be confused with a railway car) is a self-propelled railway Vehicle designed to Transport passengers One problem was that British diesel locomotives were often seriously under-powered, compared with the steam locomotives against which they were competing.

After 1945, problems associated with post-war reconstruction and the availability of cheap domestic-produced coal kept steam in widespread use throughout the two following decades. However the ready availability of cheap oil led to new dieselisation programmes from 1955 and these began to take full effect from around 1962. Towards the end of the steam era, which came about in 1968, steam motive power was allowed to fall into a dire state of repair; this along with the absence of attention given to the attendant staff working conditions could only accelerate the decline to such a degree that British Railways estimated that its steam locomotives accounted for around four times more in running costs than diesels. The use of steam locomotives in British industry continued on an ever-reducing scale into the late 1980s, but the poor availability of replacement parts, coupled with the decline of the coal mining industry, led to the disappearance of steam power for commercial uses. An industrial railway is a type of private Railway used exclusively to serve a particular industrial site either entirely within a mine or Factory

South Korea

In South Korea, the first steam locomotive was the Moga (Mogul?) 2-6-0, followed by; Sata, Pureo, Ame, Sig, Mika, Pasi, Hyeogi, Class 901, Mateo, Sori, and Tou. In the Whyte notation for the classification of Steam locomotives by Wheel arrangement, a 2-6-0 has a pair of Leading wheels followed by six Used until 1967, that locomotive is now in the Railroad Museum.

Other countries

In other countries, the conversion from steam was slower. By March 1973 in Australia, steam had vanished in all states. For a topic outline on this subject see List of basic Australia topics. Diesel locomotives were more efficient and the demand for manual labour for service and repairs was less than steam. Cheap oil had cost advantages over coal.

In the USSR, the last steam locomotive (model П36, serial number 251) was built in 1956; now in the Museum of Railway Machinery at former Warsaw Rail Terminal, Saint Petersburg, Russia. The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 Varshavsky Rail Terminal (Варша́вский вокза́л Varshavsky vokzal) or Warsaw Rail Terminal, is a former passenger Train station in Saint Petersburg ( tr: Sankt-Peterburg,) is a city and a federal subject of Russia located on the Neva River In the European part of the USSR, almost all steam locomotives were replaced by diesel and electrical ones in 1960s; in Siberia with its cheap coal, steam locomotives were in active use till mid-1970s. Siberia (Сиби́рь Sibir) is the name given to the vast region constituting almost all of Northern Asia and for the most part currently serving However, some photographs exist of Russian steam locomotives at work into the 1980s, and many accurate historical records state that Russian Decapods, L-class 2-10-0s, and LV-class 2-10-2s were retired between 1980-1985, implying that the best of Russian steam, such as the P36 class, remained on the active rosters into the 1990s. Until 1994, Russia had at least 1,000 steam locomotives stored in operable condition in case of "national emergencies" - as a result, more than 200 steam locomotives are still in working condition.

Blue Mountain and Reading Railroad number 425 being readied in Pennsylvania, U.S.A., for the daily tourist train in 1993. The Commonwealth of Pennsylvania ( often colloquially referred to as PA (its abbreviation by natives and Northeasterners is a state located in the Northeastern The United States of America —commonly referred to as the

In Finland, the first diesels were introduced in the mid-1950s and they superseded the steam locomotives during the early '60s. Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. The State Railways (VR) operated steam locomotives until 1975. VR or VR Group (VR-Yhtymä Oy VR-Group Ab is a state-owned Railway company in Finland, and formerly known as Suomen Valtion Rautatiet

In Poland, on non-electrified tracks steam locomotives were superseded almost entirely by diesels by the early '90s. Poland (Polska officially the Republic of Poland A few steam locomotives, however, operate still from Wolsztyn. Although they are maintained operational rather as a means of preserving railway heritage and as a tourist attraction, they do haul regular scheduled trains (mostly to Poznań). Poznań Lublin Voivodeship This article is about the city in Poland Apart from that, numerous railway museums and heritage railways (mostly narrow gauge) own steam locomotives in working condition. A narrow gauge railway (or narrow gauge railroad) is a Railway that has a Track gauge narrower than the of Standard gauge railways

In South Africa an oil embargo combined with an abundance of cheap local coal and a cheap labour force, ensured steam locomotives survived into the 1990s. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa In international Commerce and politics, an embargo is the prohibition of commerce Locomotive engineer L. D. Porta's designs appeared on a Class 19D engine in 1979, then a former Class 25 4-8-4 engine, became a Class 26, termed the "Red Devil" No. Livio Dante Porta ( March 21 1922 - June 10 2003) was an Argentine steam locomotive engineer 3450, which demonstrated an improved overall performance with decreased coal and water consumption. The single class 26 locomotive operated until the end of steam. Another class 25NC locomotive, No. 3454, nicknamed the "Blue Devil" because of its colour scheme, received modifications including a most obvious set of double side-by-side exhaust stacks. In southern Natal, two former South African Railway 2 ft (610 mm) gauge NGG16 Garratts operating on the privatised Port Shepstone & Alfred County Railway (ACR) received some L. D. Porta modifications in 1990 becoming a new NGG16A class. [25]

China continued to build mainline steam locomotives until late in the century, even building a few examples for American tourist operations. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Since China was the last main-line user of steam locomotives, ending officially at the beginning of 2006, it is plausible that many still exist in industrial operations or in more remote parts of China. Many coal mines and smaller cities, such as Pingdingshan and Hegang, maintain an active roster of JS, SY, or QJ steam locomotives bought secondhand from China Rail. The last steam locomotives built in China were of the SY 2-8-2 class, built until 1999. The last steam locomotive built in China was SY 1772, finished in 1999. As of 2007, at least four Chinese steam locomotives exist in the United States - 2 QJ's bought by RDC, a JS bought by the Boone Scenic Railway, and an SY bought by the NYSW for tourist operations, but re-painted and modified to represent a 1920s era US locomotive.

Hopes of revival

Dramatic increases in the cost of diesel fuel prompted several initiatives to revive steam power. [26][27] None of these has progressed to the point of production, and in the early 21st century, the steam locomotives operate only in a few isolated regions and in tourist operations. A heritage railway ( United Kingdom) preserved railway ( United Kingdom) or tourist railroad ( United States and Canada) is a

In Germany a small number of fireless steam locomotives are still working in industrial service, e. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. A fireless locomotive was a type of Locomotive designed for use under conditions restricted by either the presence of flammable material (such as in mines or the need g. at power stations.

The Swiss company Dampflokomotiv und Maschinenfabrik DLM AG delivered several new steam locomotives to rack railways in Switzerland and Austria between 1992 and 1996. A cog railway, rack-and-pinion railway or rack railway is a Railway with a toothed rack rail, usually between the running rails. Switzerland (English pronunciation; Schweiz Swiss German: Schwyz or Schwiiz Suisse Svizzera Svizra officially the Swiss Confederation Austria (Österreich ( officially the Republic of Austria (Republik Österreich One was the Brienz Rothorn Bahn. The Brienz Rothorn Bahn (BRB is an gauge tourist Rack railway in Switzerland, which climbs from Brienz at the eastern end of Lake Brienz to the summit of the

Steam locomotives in numismatics

The Biedermeier Period coin featuring a steam locomotive

Steam locomotives have left such a legacy behind, that they have been the main topic for numerous collectors and bullion coins. Euro gold and silver commemorative coins are special Euro coins minted and issued by member states of the Eurozone. On of the most recent ones is the famous 20 euro Biedermeier Period coin, minted in June 11, 2003. Euro gold and silver commemorative coins are special Euro coins minted and issued by member states of the Eurozone. Events 1184 BC - Trojan War: Troy is sacked and burned according to the calculations of Eratosthenes. Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. The obverse of the coin shows a premature steam locomotive (the AJAX) on Austria's first railway line, the Kaiser Ferdinand's Nordbahn. The Northern Railway (Nordbahn KFNB Severní dráha císaře Ferdinanda SDCF was the name of a former Railway company during the time of the Austro-Hungarian monarchy The AJAX can still be seen today in the Austrian railway museum.

References

1. ^ a b Payton, Philip (2004). Oxford Dictionary of National Biography. Oxford University Press.
2. ^ Young, Robert (2000). Timothy Hackworth and the Locomotive. Lewes, UK: the Book Guild Ltd.
3. ^ Hamilton Ellis (1968). The Pictorial Encyclopedia of Railways. The Hamlyn Publishing Group, pp. 24-30.
4. ^ See section of the LNER Class A1/A3 article on the sharp increase in availability brought about in this respect by the application of the Kylchap exhaust to Gresley Pacifics in the early 1960s
5. ^ "West Coast and R711". Disambiguation LNER Thompson Class A1/1, LNER Peppercorn Class A1 The London and North Eastern Railway LNER The Kylchap Steam locomotive exhaust system was designed and patented by the famous French steam engineer André Chapelon, using a second-stage aus.rail. (Web link).
6. ^ a b c d Swengel p. 146
7. ^ Scott, Ron; GN Large Atlantics (Profile Publications Berks UK - no date), p. 129
8. ^ a b c d e f g Bell, A Morton (1950). Locomotives, seventh edition, London: Virtue & Co Ltd,.
9. ^ White, John H. Jr. (1968). A history of the American locomotive, its development: 1830-1880, (Reprint: Dover Publications, New York 1979), Baltimore, USA: John Hopkins Press, pp. 146-149.
10. ^ a b c Snell (1971). Mechanical Engineering: Railways.
11. ^ White, J. ibid, pp. 114-124.
12. ^ a b (1957) Handbook for Railway Steam Locomotive Enginemen. British Transport Commission.
13. ^ "Cass City Chronicle" (PDF) (Friday, July 29, 1938). Cass City Chronicle: p 3.
14. ^ Pennsylvania Railroad chemical laboratory. U. S. National Parks Service online history resource. Retrieved on 2006-11-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 694 - Egica, a king of the Visigoths of Hispania, accuses Jews of aiding Muslims sentencing all
15. ^ Oxford English Dictionary: Buff 1
16. ^ (1842) Railway Regulation Act. The Oxford English Dictionary ( OED) published by the Oxford University Press (OUP is a comprehensive Dictionary of the English Her Majesty's Stationery Office.
17. ^ Van Riemsdijk, John T. (1994). Compound locomotives, an international survey. Penryn, England: Atlantic Transport Publishers. ISBN 0 906899 61 3.
18. ^ David Ross, The Steam Locomotive: a History, Tempus Publishing, Gloucestershire, 2006, ISBN 0-7524-3916-2
19. ^ Pennsylvania Railroad locomotive classification@Everything2.com
20. ^ Adams, Henry (1908). Cassell's Engineer's Handbook. London: Cassell and Company, p389.
21. ^ Allen, Cecil J (1949). Locomotive Practice and Performance in the Twentieth Century. Cambridge, England: W Heffer and Sons Ltd.
22. ^ 1935 article on the advantages of diesel locomotives.
23. ^ (1962) Diesel Traction Manual for Enginemen. British Transport Commission, pp. 15-16.
24. ^ Last locomotive to operate in the United States. Library Service of Northern Illinois University. Retrieved on 2007-11-05. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1499 - Publication of the Catholicon in Treguier ( Brittany)
25. ^ VidRail Productions, South African end of Steam: Orange Free State, Part 4, Vols. 3, 4 and 5 and Natal, Part 3, Vol. 1, in The Best of Southern African Steam, 1983-1990
26. ^ The 5AT project to develop a modern steam locomotive for British railways.
27. ^ Railway Extension Across the Andes: reactivation and modernisation of existing fleet of 75 cm gauge 2-10-2 steam locomotives.