This list of transportation technology research paper topics provides the list of 30 potential topics for research papers and an overview article on the development of transportation technology.
1. Air Traffic Control Systems
When a technology is fully assimilated, it is relatively invisible. Such is the way with air traffic control. It seems to go on all around us without our caring much about it, even if we fly. Air traffic control began via the mail service. The airmail had to be delivered, and many new routes in strange places were pioneered by the need to fly mail. Mail pilots used writing on building roofs below to guide them during the day and various lights at night. However, most of the congestion was at the airports themselves. Controllers would be stationed in a tower or at the end of a runway and would use light signals (still the same ones used in a communications failure today) to guide landings or to hold aircraft for a break in the traffic.
2. Aircraft Design
No innovation is more distinctive of the twentieth century, or more influential on its life or imagination, than the airplane. While the root technologies were established in the nineteenth century, it was the Wright brothers in 1903 who first synthesized them into a machine capable of sustained, controlled flight. Heavier-than-air flight stretched the limits of engine power and structural strength per unit weight and gave great impetus to technology, with influence far beyond aeronautics. It also largely initiated the engineering science of aerodynamics, again with far-reaching implications. The scope of aircraft design through the twentieth century can be considered by viewing the developments of four types of aircraft:
- Biplane and externally braced wings
- Streamlined monoplanes
- Transonic aircraft
- Supersonic and hypersonic aircraft.
3. Aircraft Instrumentation
When Wilbur Wright took off from Kitty Hawk, North Carolina in December 1903, the only instruments on board the first successful powered heavier-than-air machine were a stopwatch and a revolution counter. The historical first flight began the quest to improve aircraft as machines to conquer the air, and instrumentation evolved accordingly. Aircraft instrumentation can be divided into four categories: engine performance, communications, ground-based instruments, and air-based radar.
An automobile is commonly defined as a self-propelled, minimum three-wheeled vehicle for passenger or freight transport on ordinary roads. Today’s cars are commonly driven by an internal combustion engine using volatile fuel. Without any doubt, the motor vehicle is among the technological developments of the twentieth century with the most far-reaching social and economic consequences. Automobile production became a major industry in many industrialized countries and had a decisive influence on the development of modern mass production technologies. Furthermore, by deeply transforming the living habits of people, automobiles became an integral part of modern western culture.
The first catamarans (boats with two hulls) were derived from the traditional paddled rafts used by natives of Polynesia. These boats, which were essentially two canoes joined with logs, powered by a single sail, provided great stability and allowed them to travel vast distances on the open ocean. In Europe, the history of catamarans begins with Sir William Petty (1623–1687). Petty studied the hydrodynamics of model hulls and found that a long, slim hull travels more easily through water than a wide one. The ratio of hull length to hull width, now called the ‘‘fineness,’’ ‘‘slenderness,’’ or ‘‘displacement-to-length’’ ratio, is the key determinant of hydrodynamic performance. Within certain constraints that we will look at below, a slender hull has less drag and creates less of a bow wave, both of which slow down the movement of boats through the water.
6. Diesel and Diesel Electric Locomotives
Electronics has transformed the diesel locomotive. Component size has been reduced. Solid-state rectifiers enabled the DC generator to be replaced by the smaller alternating current (AC) alternator. The solid-state inverter and control apparatus enabled the asynchronous motor to replace the traditional DC traction motor. Globalization of industries in the 1980s led to designs for a universal diesel locomotive able to work anywhere in the world. This philosophy gave way to the modular policy of building diesel and electric units, from heavy goods engines to TGV, using common components. At the close of the twentieth century, European companies cooperated with North American combines to produce global designs, and GM diesel-electric locomotives made in North America were at work in Europe. The diesel locomotive continued to develop: driverless working was demonstrated; and experiments to operate diesel locomotives with hydrogen, coal-based fuels, methane and other gases, and coal-slurry have been carried out. Though it cannot match the very high performance of the electric locomotive, the diesel is ideal for all operations outside electrified zones.
From the time of the first balloon ascents in France in 1783, the problem of steering airships became obvious because of dependence on the wind for direction and on gas quantity and pressure inside the envelope for altitude control. It would take over a century of experimentation with gas inflation, propulsion, and altitude and directional control for airships to become practical. The wildest solutions were proposed to solve the problem of dirigibility, but serious, scientific-based proposals also appeared. One of the first was that of Jean-Baptiste Meusnier’s 1783 ellipsoid-shaped balloon, which was never built. His design included the concept of a ballonet, a gas container within the envelope (with the space in between filled with air) to keep the hydrogen and of a mechanical valve atop the balloon intended to release hydrogen on command, thus allowing better control of ascent and descent phases. While both concepts would eventually be incorporated into both balloons and dirigibles, the matter of propulsion remained difficult to solve.
8. Electric Automobiles
Since its development in the 1890s, the electric automobile has always been the car of tomorrow. Many of the earliest motor vehicles employed electric technology, and thousands of electric vehicles provided satisfactory transport service in the U.S. and Europe over the course of the twentieth century. Never as incapable as its critics claimed, neither was the electric automobile ever destined to become the ‘‘universal’’ vehicle of choice for the typical driver. In specific places and times and for select applications, the electric vehicle excelled, but it has never managed to live up to its lofty expectations.
9. Electric Locomotives
Electric locomotion grew from nineteenth century electrification of quarries, mines, light railways, and cable car systems, and basic forms were established in the street trolleys of the 1880s in the U.S. Heavy-duty electric traction evolved in the 1890s on rapid transit railways in large cities like Chicago and New York. Low-voltage direct current (LVDC) technology, using rotary converters and conductor rails, was needed for terminal and tunnel lines, where locomotives were required. Locomotives equal in power to any steam locomotive were working in the period from 1900–1910. Overall energy efficiency was low if power came from coal stations and electric traction was employed to meet legal requirements or operational needs. Early locomotives took many forms: some used body-mounted motors driving through rods and shafts; others used geared axle-mounted nose-suspended motors. Other than heavy-duty rapid-transit railways, electric traction could not replace steam traction on general-purpose railways. The Pennsylvania Railroad and New York Central terminal lines and the Detroit and Baltimore tunnel lines were early locomotive worked railways.
10. Fly-by-Wire Systems
Most civilian and military aircraft are today controlled by ‘‘fly-by-wire’’ systems, in which controls are operated electrically, permitting greater maneuverability and safety than in conventional mechanically based control systems. Conventional flight control works as the pilot transmits directions through the control devices and the control surfaces are actuated according to the pilot’s input. In larger airplanes, there is also a hydraulic system, like the power steering on an automobile, to actuate the control surfaces.
A fly-by-wire system breaks the mechanical lineages—a computer is added. Pilot input through the stick and rudder pedals are converted from a deflection to a voltage proportional to the deflection, and then the voltage is passed on to the computer, where it is further converted to binary numbers. Air data sensors are also connected to the computer. The computer then compares the pilot’s desires to the actual state of the airplane and sends signals to reconcile them. These signals are converted back into voltages and used by electric servos at the hydraulics to move the control surfaces.
11. Foodstuffs Transport
Twentieth century foodstuffs were transported by land on vehicles and trains, by air on cargo planes, and by water on ships or barges. Based on innovations used in previous centuries, engineers developed agricultural technology such as refrigerated containers to ship perishable goods to distant markets. Technological advancements enabled food transportation to occur between countries and continents. International agreements outlined acceptable transportation modes and methods for shipping perishables. Such long-distance food transportation allowed people in different regions of the world to gain access to foodstuffs previously unavailable and incorporate new products they liked into their diets. Refrigerated trailers dominate road food transportation methods. This transportation mode minimizes food vulnerability to shipment damage from being harvested to placement on grocery shelves. Refrigerated transport enables fresh produce from milder climates to be shipped out-of-season to colder locations. Refrigeration is achieved by mechanical or cryogenic refrigeration or by packing or covering foods in ice. Ventilation keeps produce cool by absorbing heat created by food respiration and transferred through the walls and floor from the external air beneath and around the shipping trailer. Food technologists design packaging materials for food transportation. Most produce is shipped in corrugated and fiberboard cardboard boxes that are sometimes coated with wax. Wooden and wire-bound crates are also used in addition to bushel hampers and bins. Mesh plastic, burlap, and paper bags hold produce. Meat is often vacuum packed on plastic trays that are placed in wooden lugs. Foods are occasionally wrapped in plastic liners or packed in ice to withstand damage in transit and limit evaporation.
12. Gas Turbines in Aircraft
Based on the technology of the land-locked and heavy steam turbine, by the mid-1930s development began in earnest on the gas turbine for aircraft. In the end, the evolutionary development in technology had a revolutionary impact on transportation systems.
The turbojet engine for aircraft is a connected three-stage system. The compressor, in either the axial-flow or centrifugal-flow form (or a combination thereof), compresses entering air. The compressed air enters the next stage—single or multiple combustion chambers—where it is mixed with fuel and fired. The super-heated, expanded air flows over a turbine as it exits the system, producing thrust in the form of exhaust. The turbine is connected to the compressor on a rotating shaft (or shafts) that turns the entire system. The rotational forces of the turbojet system are not as strenuous as those in a conventional piston engine, and are therefore more mechanically efficient. Although the thrust in the form of exhaust is the most simplified use of the turbojet engine, the shaft horsepower can also be harnessed to drive propellers, drive gears, or applied to other uses (e.g., the 1950s American Chrysler Turbine automobile).
Though the overall shape of the helicopter has not changed much since Sikorsky’s original patent, various innovations and materials have contributed to improving its performance. These range from the use of carbon composites, to placing the tail rotor within the axis of the tail to reduce noise. More recently, the use of directional outlets to blow air out of the tail (the NOTAR principle) has appeared as a way to replace the tail rotor.
14. High Speed Railways
High speed railway operations in the twentieth century resulted from deliberate attempts to work a system at speeds much higher than the maximum speeds attained on conventional railways, with competition for the shortest time on routes between large cities; for example, passenger train rivalry on routes between New York and Chicago in the 1930s. High-speed railways required construction of new lines; segregation of operations; new forms of rolling stock, and unorthodox methods of propulsion relying on techniques developed outside the railway industry. However, the great success of the segregated high-speed railway is a post-1960s phenomenon.
Cars, which were originally designed as intraurban alternatives to horse-drawn carriages, could only be transformed into major carriers of regional and long-distance transportation with thoroughfares connecting urban centers. A highway is generally defined as a multilane road with separate lanes for each direction, separated by a median or crash barrier, to which access is limited both technically through entry and exit ramps and legally by only allowing cars and trucks to use these roads. Many countries require minimum speeds on their highways; all countries, with the exception of Germany and some U.S. states, limit the maximum speed. Often equipped with their own police, service stations, rest areas, and road crews, these roads have become institutions of their own, especially in those countries where they are run by separate public or private bodies. Research into surfacing, soil treatment, and the planning of interchanges, has contributed to the growth of these networks.
16. Hovercraft, Hydrofoils, and Hydroplanes
These three vehicle types combine aspects of flying and floating in hybrid marine craft capable of far higher speeds than traditional boat hulls. They accomplish this feat, valuable in commercial ferries, military vehicles, and racing boats, in very different ways.
17. Human Power Transport
Human-powered transport in the form of bicycles and tricycles has played an important—though often unrecognized—role in developments since the nineteenth century in industrial practices, human mobility, and sporting achievement. It has stimulated engineering innovation far beyond its own boundaries. Henry Ford and the Wright Brothers all began their careers as bicycle mechanics, and bicycles continue to be used because of their simplicity of design as a testing ground for new innovations in materials and bonding methods.
18. Hybrid Automobiles
In technology, as in biology, a hybrid is the result of ‘‘cross-fertilization,’’ in this case referring to the application of technologies to produce a similar yet slightly different entity. Recent research in the history of automotive technology shows that hybridization has been much more common than previously thought. Thus, the automobile itself can be viewed as a hybrid with a century-long history of crossover phenomena from electrical engineering to mechanical engineering that resulted in an ‘‘electrified gasoline car.’’
19. Internal Combustion Automobiles
Modern standard automobiles are driven by engines working according to the principle of internal combustion; that is, the pressure resulting from the combustion of an air and fuel mixture that is directly transformed into mechanical work. Otto engines, first built in 1877 by the German engineer Nikolaus Otto, are the standard engines for gasoline-powered cars. The only other significant and commercially successful internal combustion engine has been the diesel, developed by the German engineer Rudolf Diesel. These engines have become the standard because they are smaller, lighter, and more efficient when compared with other combustion engines of the same power.
20. Internal Combustion Piston Engine
Born in the nineteenth century, the internal combustion piston engine did not come of age until the twentieth century. Through a long stream of refinements and expansion into a variety of sizes, shapes, and types, this device must be considered among the most influential technological developments in human history. Internal combustion piston engines, such as those used to power model aircraft, can be small enough to fit in the palm of the hand. At the other end of the spectrum, engines used to operate power generators, ships, or rail locomotives can weigh several tons and take up the space of an entire room.
21. Jet Driven Civil Aircraft
The development of jet power shortly before World War II resulted in a series of transport projects designed during the conflict, especially in England. The jet principle seemed simple in theory. Air drawn through an intake is compressed through the engine nacelle by turbine-powered rotating blades, mixed with injected kerosene, which is then burned to create energy and rear-flowing exhaust gas. In fact, the internal engine dynamics, such as compression rates, temperature, and the fuel injection system all required considerable experimentation, with military jets becoming the first to be powered that way.
Without the bicycle there was nothing to motorize. Originating in France in the late 1770s, the hobbyhorse became the safety bicycle over 110 years through many people’s efforts, including Thomas Humber, Dan Rudge, George Singer, James Starley, and Harry Lawson. Lawson’s patent of 30 September 1879 shows a pedalpowered, rear-wheel chain-driven bicycle, something perfected by John Kemp Starley and William Sutton in 1885. The technology to motorize a bicycle had existed for years. A German-built steam-driven velocipede is shown in a drawing dated 5 April 1818. Sylvester Roper of Roxbury, Massachusetts, exhibited a bicycle with a charcoal-fired two-cylinder engine at fairs in the eastern U.S. in 1867, and in France, the Michaux-Perreaux was built in 1868 by attaching a small commercial steam engine to a bicycle.
23. Propeller Driven Civil Aircraft
The advent of early commercial propeller aircraft followed in the wake of World War I, when manufacturers modified bomber models in response to airline demand. Thus, the Farman Company developed the Goliath model, which was used in early Paris to London links beginning in 1919. Along similar lines, using a modified Vickers Vimy, British pilots Alcock and Brown were able to cross the Atlantic that same year. However, their exploits and those of Charles Lindbergh notwithstanding, propeller aviation in the interwar years focused primarily on short and medium range aircraft. As engine and airplane design improved the range of machines, some were used for long-distance mail transport.
24. Railway Mechanics
Railway mechanics grew from the nineteenth-century analysis of the union of locomotive and track. Improving the ‘‘fit’’ between engine and track was essential for safe and progressive operation. Analysis of the new machine stimulated general engineering mechanics. Investigators studied the balancing of locomotive mechanisms in the nineteenth century, and the phenomenon of fatigue failure was first identified in a locomotive context. In the early twentieth century, the study of shatter cracks in rail heads resulted in new regulations governing the manufacture of rails. Sylvester and Tschebyshev considered the kinematics of mechanisms, including valve gears. O. Reynolds studied balancing of reciprocating parts, and coupling rod failure. Railway studies of materials are reflected in the work of Mohr, whose analysis is still used in strength of materials.
25. Rocket Planes
Once the Wright brothers had proved that controlled and sustained powered flight was possible, two related avenues of development were immediately apparent: increasing the distance and the speed of flight. From that first flight in 1903 until the late 1930s, aircraft control and propulsion technology was developed to improve all aspects of flight, culminating in the production of the subsonic turbojet. Although further development of the jet engine would revolutionize both military and commercial aviation and boost speeds into the supersonic region, what became known as the ‘‘sound barrier’’ (Mach 1) was first broken by a rocket-powered aircraft, the XS-1.
The era of the steam-propelled ship began in 1807 when Robert Fulton’s Clermont paddle-wheeled up the Hudson River to Albany, New York. Steam application to ship technology progressed so rapidly that in only 30 years the Great Western, a 72-meter wooden paddle-wheeler owned by the Great Western Railway, was able to sail from Bristol to New York in 15 days and establish itself as the first steamship to perform regular service between the U.S. and Britain. The next seagoing milestone came in 1843 when the cargo ship SS Great Britain, with an iron hull, a state-of-the-art engine, and a propeller-driven thrust system, was launched in Bristol. Although it still carried masts and sails, the three elements of a modern cargo ship were present: iron hull, steam engine, and propeller drive. By 1914 the triple expansion reciprocating steam engine was developed and remained in use through the century. The first steam turbine for marine propulsion, built for demonstration purposes only, was Charles Parsons’ Turbinia in 1894. Turbines were adopted for Navy ships such as HMS Dreadnought and in 1905 the first turbine-powered large ocean liner was built. The Titanic also carried a Parsons steam turbine engine. In 1912 the first cargo ship to be powered by an internal combustion engine was built. At the conclusion of World War I, some 300 ‘‘motor ships’’ were in operation. In addition to engine technology, improvements were made in hull design, cargo handling, fuel usage, and ease of repair.
27. Steam Locomotives
In 1900 British influence on the design of steam locomotives was strong but existed alongside distinct French, German, and American traditions. In the twentieth century, American designs and organization of steam traction became global standards due to research by universities, railroads, and the engineering industry. After 1900, North American designs departed radically from their European counterparts and became heavier in size, weight, tractive effort, and power. The basic ‘‘Stephenson’’ locomotive remained the norm throughout the twentieth century and was improved by superheating, piston valves, and the rational proportions pioneered by W.F.M. Goss and William Woodard in the U.S. Radical departures from this norm failed and were always rare. For general-purpose railways outside rapid transit systems, there was no alternative to steam traction before the 1940s. Throughout the century, express passenger locomotives worked heavier trains at sustained speeds higher than in the period from 1890 to 1910, but top speeds did not increase much apart from a few record runs of over 160 kilometers per hour (km/h), and steam traction coped until the 1950s. (The world speed record for steam was set at 203 km/h in 1935 by the British 4-6-2 engine Mallard.) From 1900 to 1930 freight trains of 3000 to 6000 tons were moved at 8–16 km/h mph and required engines with high tractive effort, low speed, and moderate power. The compound-expansion Mallet type, weighing up to 350 tons, was employed in the U.S. for this duty. After 1930, operations favored lighter, faster trains, and the high-powered, high-speed, rigid-framed 2-8-4 or 2-10-4 wheel arrangement type was widely used.
Beginning in the 1860s, and up to World War I, most submersible inventions were marketed for their military potential. After World War I, however, interests in oceanic exploration, for purposes ranging from scientific research to resource exploitation and wreckage recovery, prompted the development of several types of civilian submersibles. A further reason for the development of submersibles was an understanding of the limit of the human body to withstand great depths. Initially, diving bells were the basic means of underwater exploration, but by the twentieth century it was clear that no amount of improvement to the open diving bell (where the air became more compressed as the depth increased) could compete with enclosed habitats.
29. Supersonic Civil Aircraft
When the jet age began revolutionizing air travel by halving flight time and doubling passenger numbers in the 1950s, supersonic transport (SST) appeared to be the logical next stage in the progress of commercial aviation. But while the dynamics and challenges of supersonic flight were clearly defined (the speed of sound, Mach 1, ranges between 1000 and 1200 kilometers per hour)), applying them to civilian transportation remained extremely difficult. The challenges included propulsion, weight distribution (on military aircraft the payload is easily predetermined), passenger comfort and, as it would soon become clear, economic efficiency. Several nations undertook studies of supersonic transport in the late 1950s including the U.S., the Soviet Union, the U.K, and France.
30. Urban Transportation
All the forms of urban transit popular in the twentieth century—buses, streetcars or trams, trolleybuses, cable cars, railroads, and subways— had their origins in the nineteenth century or before. In that century they merely served towns and cities, but in the twentieth century, enhanced mainly by electrical technology, they helped to create new and enlarged communities.
The Development of Transportation Technology
During the twentieth century, human beings witnessed a revolution in transportation technology. The way in which people and goods moved around the world changed dramatically. The nineteenth century, of course, also had its transportation revolution, as railroads and steam ships became dominant, and these forms of mass travel did not disappear during the twentieth century. Transport by sea continued to play a key role in the movement of people and cargoes, as ships became bigger and faster, culminating in giant super tankers used to transport oil around the world. Railroads also evolved, shifted to electric and diesel power. By the late twentieth century, high-speed trains whisked passengers to their destinations at speeds of up to 270 kilometers per hour.
The internal combustion engine led to widespread use of automobiles, buses, and trucks. Trucks, for example, would provide fierce competition for the railroads in the movement of goods across land. The development of aircraft also transformed travel around the globe. The use of airplanes to carry passengers and cargoes greatly reduced travel time. Journeys across the oceans were now measured in hours rather than in days and weeks.
Transportation over water continued to play an important role in the twentieth century. Intense competition among shipping lines had begun in the mid-nineteenth century as immigration from Europe to the Americas grew. Shipping lines sought to build bigger and more luxurious ocean liners in hopes of attracting first- and second-class passengers. By the early twentieth century, the Hamburg–America Line was the largest shipping company, covering 75 routes with 500 vessels. Rivalries among these shipping lines meant that the companies continually put bigger and faster ships into service, leading to much turnover in their fleets, as older vessels quickly became outdated. This competition also led to a price war in the years before World War I. Lower prices led to a notable increase in emigrant traffic in this period.
At the turn of the century, the U.S. sought to become more involved in the transatlantic shipping business. In 1902, J.P. Morgan formed the International Mercantile Marine Company. Morgan either bought or made cooperative agreements with numerous existing shipping lines. His biggest competitor was the Cunard Steamship Company, a British line. In order to combat Morgan, the Cunard line received subsidies and loans from the British government. It was then able to construct two 35,000-ton liners and in 1903 inaugurated direct service from Italy to New York. The Morgan–Cunard rivalry led to a rate war in 1904, which eventually led to the end of Morgan’s venture in 1926.
Despite technological advances, sailing ships did not disappear immediately. However, by the early twentieth century, they had mostly been pushed to more marginal trade. There remained some important transoceanic routes for sailing ships, such as guano from South America, grain from Australia and Argentina, and timber from Africa and Asia. These sailing ships continued to operate where large cargo ships could fill their holds and find favorable winds. However, there were only a few holdovers that lasted until after World War II.
Most cargo was carried by tramp steamers, a business dominated by the British. These tramp steamers could carry cargoes of up to 10,000 tons while traveling at 13 knots. They consumed 70 tons of coal per day. They were some 140 meters long and 16 feet wide and were manned by a crew of 75.
Shipping in the early twentieth century was aided by the construction of the Panama Canal. This canal stretches 65 kilometers from shoreline to shoreline across the Isthmus of Panama, connecting the Atlantic and Pacific Oceans. Along with the Suez Canal, the Panama Canal became one of the two most strategic artificial waterways in the world. The canal opened to traffic in 1914 and was controlled by the U.S. until 2000 when control reverted to Panama. The great advantage of the Panama Canal was that ships no longer had to carry their cargoes and passengers around Cape Horn at the southern tip of South America, thus shortening the journey between the east and west coasts of the U.S. by some 8,000 nautical miles (14,800 kilometers).
Another technological development in the movement of goods around the world by sea was the increased use of tankers. The first tankers had been used in the late nineteenth century to transport oil. There was much concern over the use of tankers, particularly due to the threat of explosions. For this reason, tankers were not allowed through the Suez Canal until 1902. As petroleum became an increasingly important product in the early twentieth century, tanker freights increased dramatically. At first, most tankers were owned by the oil companies themselves. Later, private companies became involved, leasing their tankers to the large oil firms.
World War II saw important developments in the movement of people and goods across the seas. In particular, shipbuilding in the U.S. was a key factor in the Allied victory. U.S. shipyards produced an enormous fleet that kept the Allies supplied with constant convoys of materials and troops across both the Atlantic and Pacific Oceans. The most important of the ships produced during the war were the Liberty ships, of which 2650 were built between 1941 and 1944. Among the advances seen in the construction of the Liberty ships was that large sections were produced and then welded together. They had steel decks, and were powered by reciprocating steam engines fed by oil-fired boilers.
The postwar years saw an important evolution of shipping technology, as larger tankers and bulk carriers made their appearance. These developments were linked to a significant increase in world trade following the war. Ships became much faster, reaching speeds of 20 knots. There was also much concern over appearance as esthetically pleasing ships were built. Shipbuilders also tried to streamline the loading and unloading of cargo, introducing for example the loading pallet in 1958.
Perhaps the key development in the movement of goods by sea in the postwar era was the fact that oil became the key to the world economy. By the early 1950s, about 40 percent of sea trade was in petroleum products and the total amount of crude oil and gasoline shipped by tanker nearly tripled in the decade. There was already a plentiful supply of 16,000 deadweight ton (dwt) tankers built during the war. However, as oil consumption continued to grow, there was increased demand for higher capacity tankers. Soon, shipbuilders were constructing 50,000 dwt supertankers, which greatly reduced the cost of transport. These supertankers led to many other technological changes, including the need for larger building berths in shipyards, larger dry docks in repair yards, the construction of new terminal berths and storage facilities by oil companies. Changes in shipbuilding were often led by the Japanese, who pioneered the mass production of tankers in their shipyards, using large cranes to lift huge subassemblies and taking the lead in the use of computers in shipbuilding. At first the 50,000- to 60,000-dwt tankers were seen as the limit in size, as larger tankers could not pass through the Suez Canal. However, by 1970, there were tankers of 200,000 to 300,000 dwt.
By the early-twentieth century, railroads had reached maturity. At the time of World War I, there were about 1.6 million kilometers of railroad track around the world, with some 25 percent located in the U.S. During the first half of the twentieth century, new railroad construction slowed in most of the developed world. However, in other parts of the world, the building of new railways continued. Such was the case in Canada, China, Russia, and parts of Africa. A prominent example of this new construction was the completion of the Trans-Siberian Railroad in Russia. Work had begun on the railroad in 1891. In 1904, all of the sections between Moscow and Vladivostok had been completed. However, Russia had secured permission from China to build part of the line across Manchuria. After the Russo–Japanese War in 1904–1905, Russia feared Japan might take over Manchuria, and proceeded to build an alternative route across Russian territory known as the Amur Railway. This section was completed in 1916.
Another impressive railroad engineering feat of the early twentieth century was the completion of the Simplon Tunnel in the Alps, which despite many serious problems was opened to railroad traffic in 1906. One of world’s longest railway tunnels at 20 kilometers long, it connected Iselle, Italy to Brig, Switzerland. The Simplon Pass had been an important European trade route for centuries. In the 1890s, a German engineering firm undertook construction of the Simplon tunnel using many new tunneling techniques. Other technological developments to aid railroad transportation in the twentieth century included electric signaling systems and the widespread adoption of diesel traction. By the late 1930s, the use of diesel power had occurred in many places as it proved more reliable and efficient than steam power. In most railroad networks, diesel locomotives are more cost effective than electric ones, which is generally only profitable in very high-traffic areas such as metropolitan commuter systems.
Electrification became more widespread in the second half of the twentieth century. The French pioneered electrification of locomotives with a direct supply of high-voltage alternating current at the industrial frequency. These French developments in turn led to subsequent large-scale electrification programs in countries such as China, Japan, South Korea, the Soviet Union, and India. Such conversions to electric traction were also encouraged by the high price of oil during the 1970s.
As was the case in the early twentieth century, some countries expanded their railroad networks in the latter part of the century. This was particularly true in countries that were undertaking major industrialization projects and where railroads were still the principal form of moving people and goods. Examples include China, the Soviet Union, and India. These countries built new rail lines in order to increase their capacity to carry raw materials to industrial areas of their countries. For example, China doubled the length of its rail network between 1950 and 1990, including numerous routes of up to 800 kilometers that connected coal fields in the west to the ports on the east coast. During the same period, the Soviet Union built 32,000 kilometers of new rail lines. This new construction included the more than 3000-kilometer- long Baikal–Amur Trans-Siberian Railroad that was started in the late 1970s. During the 1990s, India also undertook major railroad construction.
In other parts of the world, there was less new construction. Here, there was an emphasis on improving rail communications, especially in light of growing competition from highway construction and air travel. Railroad companies sought to improve passenger amenities, develop larger and more specialized freight cars, design more sophisticated signaling and traffic control, and improve motive power.
Two major railway tunnels built in the second half of the twentieth century were Seikan Tunnel in Japan and the Channel Tunnel connecting England and France. The Saikan Tunnel connects the islands of Honshu and Hokkaido and is the world’s longest tunnel at 53.8 kilometers. The Japanese National Railways sponsored construction of the tunnel between 1964 and 1988. The tunnel has quickly become of limited use, as air travel between the islands is faster and almost as cheap. Nearly as long at 31 miles, the Channel Tunnel, popularly called the ‘‘Chunnel,’’ provides freight and passenger railroad service on trains that can travel up to 160 kilometers per hour. Digging began in 1987 and the tunnel opened in 1994.
The most significant development in rail transportation was an emphasis on high-speed trains, and Japan pioneered this development. In 1957, the Japanese government concluded that the old Tokyo–Osaka line could not be upgraded to meet the needs of the heavily populated and industrialized Tokaido coastal belt between the two cities. In 1959, work began on a 500-kilometer-long line for electric passenger trains. The first Shinkansen (New Trunk Line) opened in 1964. Initially able to travel at speeds of 210 kilometers per hour, the high-speed line was a commercial success. From the 1970s through the 1990s, Japan extended its network of high-speed trains, some of which reached speeds of 274 kilometers per hour. In Europe, France took the lead in developing a system of high-speed trains. The first Train a Grande Vitesse (TGV) between Paris and Lyon went into service in 1981, the result of some twenty years of research. France built and planned additional lines with an ultimate goal of connecting all major cities with Paris as well as connecting with the high-speed systems in neighboring countries. Other European nations, including Italy, Germany, and Spain have also developed high-speed trains.
Railroads faced competition from commercial trucking throughout the twentieth century. Gottlieb Daimler built the first motor truck in Germany in 1896. In the U.S., truck transportation began at the turn of the century. The Winston Company of Cleveland, Ohio began building trucks in 1898, making it one of the first truck manufacturers in the U.S. In 1904, there were a mere 700 trucks in use. This figure had increased to more than 150,000 by 1915. The first transcontinental coast-to-coast truck trip occurred in 1911, completed in 66 days. Early trucks were used mainly for making local deliveries and limited commerce between cities. Their usefulness was hindered by poor roads and the dominance of railroads in shipping goods over long distances.
However, before trucks could compete effectively with railroads, the country needed a system of well-paved roads. In 1916, the U.S. government passed the Federal Aid Road Act, which emphasized the construction of high-quality hard-surface pavements and highways for motor transportation, which helped intercity commerce utilizing trucks. As with other technologies, World War I played a key role in the development of motor trucks. In 1914, annual U.S. truck production was 24,900. By 1917, the country was producing 128,000 trucks. Many of these trucks went to Europe for the war effort to move soldiers and supplies and serve as ambulances. Because railroad arteries were often clogged during the war, large truck caravans were organized to drive the new trucks to East Coast ports from assembly plants in the Midwest. The trucks were also loaded with goods, demonstrating the possibilities for long-distance trucking and also calling further attention to the need for system of highways.
The use of aircraft would drastically alter the way in which people and goods traveled around the world during the twentieth century. Experiments with flight were not new in the twentieth century. The French had pioneered the use of balloons in the late-eighteenth century. In the late nineteenth century, the German Otto Lilenthal successfully flew gliders. Others had begun experiments with lighter-than-air dirigibles. The German Count Ferdinand von Zeppelin carried out the most important work, including the creation of a rigid but light frame that allowed for easier steering. Following Zeppelin’s advancements, in 1910 the German company Deutsche Luftschiffahuts AG (Delag) was organized and took the lead in transporting passengers in its airships. Between 1910 and 1914, Delag carried more than 34,000 passengers. Such service continued after World War I, when the Graf Zeppelin flew more than 1.6 million kilometers in commercial service. However, commercial lighter-than-air service effectively came to end when the zeppelin Hindenburg exploded in 1937.
Inspired by Lilenthal, the young mechanics Wilbur and Orville Wright in the U.S. built the first aircraft that was heavier than air and able to maneuver in flight. In December 1903 the Wright brothers made the world’s first successful flight, success based on the fact that it was a powered, sustained, and controlled flight that carried a human being.
Following the success of the Wright brothers, human beings would be fascinated with aviation, inspiring new designs and expanding the use of aircraft. The first commercial service was between Tampa and St. Petersburg, Florida, but expansion was further hastened by World War I and stories of World War I flying aces who captured the attention of the public. While commercial developments were interrupted by the war, there were many technical developments made during the conflict. During the 1920s, aviation was mainly a sport and form of entertainment. Amelia Earhart and Charles Lindburgh were among the most well-known pilots of this heroic age of flight.
At the same time, the first small commercial airlines began to operate, often to carry mail. The first were formed in 1919 in Germany, France, and Holland. These would be followed by many more during the 1920s and 1930s. Most of these early commercial airlines did not last long, either failing or merging with other airlines. In 1927, John Northrup and the Lockheed Aircraft Company developed the Vega aircraft, which served as model for modern commercial aircraft. The Vega used either 220- or 425-horsepower engines, carried a pilot and six passengers, could travel at speeds of up to 215 kilometers per hour, and had a range of between 800 and 1450 kilometers. Starting in the 1930s, airplanes were used increasingly for the transportation of people and goods. Aviation technology advanced, as monoplanes with all-metal fuselages and retractable undercarriages became widespread. In particular, three major airlines began to establish worldwide routes during the 1930s: Pan American, Imperial, and KLM.
These airlines often used seaplanes. Water provided potentially long runways at a time when most airport runways were only about 300 meters feet long. In turn, this meant that planes could be larger, use multiple engines, and have larger fuel tanks, allowing them to carry more passengers over longer distances. The 1930s also saw the introduction of first true modern commercial aircraft. In 1933, Boeing introduced its Boeing 247, to be followed by the Douglas Company’s DC-2 and DC-3. The DC-3 proved to be the first commercial aircraft to be profitable. It could fly at above 1500 meters, had a stressed aluminum sheathing that gave it considerable strength, and had a retractable landing gear. DC-3s carried most commercial traffic in the U.S. at the time, showing that commercial air travel could be safe, reliable and profitable.
The next technological advancement in the movement of people and goods through the air was the four-engine plane. Work on such aircraft had begun as early as 1913 and demand increased during the 1930s. Airlines sought to fly longer routes, such as across the Pacific Ocean, and only more powerful four-engine planes could lift enough fuel to fly such distances. Four-engine planes could also fly at higher altitudes, thus avoiding the ‘‘weather,’’ making trips faster and more comfortable for passengers. They could also fly over mountains rather around them. Another technological advance that had to accompany the four-engine planes was the pressurized cabin. An early example of this new generation of commercial aircraft was the Boeing Stratoliner, introduced in 1940.
War once again played a role in developing aviation technology. During World War II, airplanes became bigger and faster. The war was also important as the first aircraft with jet engines were introduced. After the war, there was tremendous growth of commercial air travel, led by the Stratoliner, the DC-4, and the Lockheed Constellation, all aircraft that were faster and could travel greater distances than earlier planes. By the late 1950s, more people crossed the Atlantic Ocean by plane than by ship. In the 1950s, there was some use of turboprop planes, mostly in Europe. However, the turboprop planes would soon be surpassed by the widespread use of jet engines introduced during the war. By the late 1940s, jet engines were standard in most military aircraft and by the 1950s, they were used increasingly in commercial aviation. Due to the higher speeds and lower operating costs of jet aircraft, there was a major expansion of the commercial airline industry in the second half of the twentieth century. The potential of this technology could be seen in the 1970 introduction of the Boeing 747 ‘‘jumbo jet,’’ capable of carrying up to 500 passengers.
Once jets became more widespread, the next technological advance was to produce supersonic aircraft. If successfully developed, airplanes traveling faster than the speed of sound would greatly reduce flight times around the world and revolutionize communications. Starting in 1962, France and Great Britain agreed to jointly develop a supersonic transport (SST0), known as the Concorde. The first passenger plane to break the sound barrier, however, was the Soviet Tu-144. Due to design problems, however, the Soviet craft was only in service briefly during the 1970s. The Concorde made its first flight in 1969 and entered service in 1976. It reduced the flight time between London and New York to about 3 hours. However, supersonic travel did not become profitable and also met resistance from environmental groups. In 2000, a Concorde crash outside Paris led many to reconsider the safety and value of the supersonic fleet. The Concordes were withdrawn from service because of high fuel and maintenance costs in late 2003.
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