A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels.
US Diesel Lokomotiven - Set 1
Early internal combustion locomotives and railcars used kerosene and gasoline as their fuel. Rudolf Diesel patented his first compression-ignition engine[1] in 1898, and steady improvements to the design of diesel engines reduced their physical size and improved their power-to-weight ratios to a point where one could be mounted in a locomotive. Internal combustion engines only operate efficiently within a limited power band, and while low power gasoline engines could be coupled to mechanical transmissions, the more powerful diesel engines required the development of new forms of transmission.[2][3][4][5][6] This is because clutches would need to be very large at these power levels and would not fit in a standard 2.5 m (8 ft 2 in)-wide locomotive frame, or wear too quickly to be useful.
The economic recovery from World War II caused the widespread adoption of diesel locomotives in many countries. They offered greater flexibility and performance than steam locomotives, as well as substantially lower operating and maintenance costs.[7]
The earliest recorded example of the use of an internal combustion engine in a railway locomotive is the prototype designed by William Dent Priestman, which was examined by William Thomson, 1st Baron Kelvin in 1888 who described it as a "[Priestman oil engine] mounted upon a truck which is worked on a temporary line of rails to show the adaptation of a petroleum engine for locomotive purposes."[8][9] In 1894, a 20 hp (15 kW) two-axle machine built by Priestman Brothers was used on the Hull Docks.[10][11] In 1896, an oil-engined railway locomotive was built for the Royal Arsenal in Woolwich, England, using an engine designed by Herbert Akroyd Stuart.[12] It was not a diesel, because it used a hot bulb engine (also known as a semi-diesel), but it was the precursor of the diesel.
Rudolf Diesel considered using his engine for powering locomotives in his 1893 book Theorie und Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren.[13] However, the massiveness and poor power-to-weight ratio of early diesel engines made them unsuitable for propelling land-based vehicles. Therefore, the engine's potential as a railroad prime mover was not initially recognized.[14] This changed as development reduced the size and weight of the engine.
Adolphus Busch purchased the American manufacturing rights for the diesel engine in 1898 but never applied this new form of power to transportation. He founded the Busch-Sulzer company in 1911.Only limited success was achieved in the early twentieth century with internal combustion engined railcars, due, in part, to difficulties with mechanical drive systems.[17]
Following their 1925 prototype, the AGEIR consortium produced 25 more units of 300 hp (220 kW) "60 ton" AGEIR boxcab switching locomotives between 1925 and 1928 for several New York City railroads, making them the first series-produced diesel locomotives.[30] The consortium also produced seven twin-engine "100 ton" boxcabs and one hybrid trolley/battery unit with a diesel-driven charging circuit. ALCO acquired the McIntosh & Seymour Engine Company in 1929 and entered series production of 300 hp (220 kW) and 600 hp (450 kW) single-cab switcher units in 1931. ALCO would be the pre-eminent builder of switch engines through the mid-1930s and would adapt the basic switcher design to produce versatile and highly successful, albeit relatively low powered, road locomotives.
GM, seeing the success of the custom streamliners, sought to expand the market for diesel power by producing standardized locomotives under their Electro-Motive Corporation. In 1936, EMC's new factory started production of switch engines. In 1937, the factory started producing their new E series streamlined passenger locomotives, which would be upgraded with more reliable purpose-built engines in 1938. Seeing the performance and reliability of the new 567 model engine in passenger locomotives, EMC was eager to demonstrate diesel's viability in freight service.
In many railway stations and industrial compounds, steam shunters had to be kept hot during many breaks between scattered short tasks. Therefore, diesel traction became economical for shunting before it became economical for hauling trains. The construction of diesel shunters began in 1920 in France, in 1925 in Denmark, in 1926 in the Netherlands, and in 1927 in Germany. After a few years of testing, hundreds of units were produced within a decade.
Series production of diesel locomotives in Italy began in the mid-1950s. Generally, diesel traction in Italy was of less importance than in other countries, as it was amongst the most advanced countries in the electrification of the main lines and as Italian geography makes freight transport by sea cheaper than rail transportation even on many domestic connections.
The Trans-Australian Railway built 1912 to 1917 by Commonwealth Railways (CR) passes through 2,000 km of waterless (or salt watered) desert terrain unsuitable for steam locomotives. The original engineer Henry Deane envisaged diesel operation to overcome such problems.[37] Some have suggested that the CR worked with the South Australian Railways to trial diesel traction.[38] However, the technology was not developed enough to be reliable.
Application of hydrostatic transmissions is generally limited to small shunting locomotives and rail maintenance equipment, as well as being used for non-tractive applications in diesel engines such as drives for traction motor fans.[citation needed]
The majority of British Rail's second generation passenger DMU stock used hydraulic transmission. In the 21st century, designs using hydraulic transmission include Bombardier's Turbostar, Talent, RegioSwinger families; diesel engined versions of the Siemens Desiro platform, and the Stadler Regio-Shuttle.
Steam-diesel hybrid locomotives can use steam generated from a boiler or diesel to power a piston engine. The Cristiani Compressed Steam System used a diesel engine to power a compressor to drive and recirculate steam produced by a boiler; effectively using steam as the power transmission medium, with the diesel engine being the prime mover[45]
The diesel-pneumatic locomotive was of interest in the 1930s because it offered the possibility of converting existing steam locomotives to diesel operation. The frame and cylinders of the steam locomotive would be retained and the boiler would be replaced by a diesel engine driving an air compressor. The problem was low thermal efficiency because of the large amount of energy wasted as heat in the air compressor. Attempts were made to compensate for this by using the diesel exhaust to re-heat the compressed air but these had limited success. A German proposal of 1929 did result in a prototype[46] but a similar British proposal of 1932, to use an LNER Class R1 locomotive, never got beyond the design stage.
Most diesel locomotives are capable of multiple-unit operation (MU) as a means of increasing horsepower and tractive effort when hauling heavy trains. All North American locomotives, including export models, use a standardized AAR electrical control system interconnected by a 27-pin MU cable between the units. For UK-built locomotives, a number of incompatible control systems are used, but the most common is the Blue Star system, which is electro-pneumatic and fitted to most early diesel classes. A small number of types, typically higher-powered locomotives intended for passenger only work, do not have multiple control systems. In all cases, the electrical control connections made common to all units in a consist are referred to as trainlines. The result is that all locomotives in a consist behave as one in response to the engine driver's control movements.
A standard diesel locomotive presents a very low fire risk but "flame proofing" can reduce the risk even further. This involves fitting a water-filled box to the exhaust pipe to quench any red-hot carbon particles that may be emitted. Other precautions may include a fully insulated electrical system (neither side earthed to the frame) and all electric wiring enclosed in conduit.
The flameproof diesel locomotive has replaced the fireless steam locomotive in areas of high fire risk such as oil refineries and ammunition dumps. Preserved examples of flameproof diesel locomotives include:
The lights fitted to diesel locomotives vary from country to country. North American locomotives are fitted with two headlights (for safety in case one malfunctions) and a pair of ditch lights. The latter are fitted low down at the front and are designed to make the locomotive easily visible as it approaches a grade crossing. Older locomotives may be fitted with a Gyralite or Mars Light instead of the ditch lights.
Although diesel locomotives generally emit less sulphur dioxide, a major pollutant to the environment, and greenhouse gases than steam locomotives, they are not completely clean in that respect.[49] Furthermore, like other diesel powered vehicles, they emit nitrogen oxides and fine particles, which are a risk to public health. In fact, in this last respect diesel locomotives may perform worse than steam locomotives.
For years, it was thought by American government scientists who measure air pollution that diesel locomotive engines were relatively clean and emitted far less health-threatening emissions than those of diesel trucks or other vehicles; however, the scientists discovered that because they used faulty estimates of the amount of fuel consumed by diesel locomotives, they grossly understated the amount of pollution generated annually. After revising their calculations, they concluded that the annual emissions of nitrogen oxide, a major ingredient in smog and acid rain, and soot would be by 2030 nearly twice what they originally assumed.[50][51] In Europe, where most major railways have been electrified, there is less concern. 2ff7e9595c
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