Unit world railroads in the 20-th century

UNIT 4

C)TRACK MAINTENANCE

Modern machinery enables a small group of workers to maintain a relatively long stretch of railroad track. Machines are available to do all the necessary track maintenance tasks: removing and inserting ties, tamping the ballast, cleaning the ballast, excavation and replacement of worn ballast, spiking rails, tightening bolts and aligning the track. Some machines are equipped to perform more than one task: for example, ballast tamping combined with track lining and leveling.

Mechanized equipment can renew rails either in conventional bolted lengths or with long welded lengths. A modern machine of this type has built-in devices to lift and pass old rails to flat cars and to bring forward and deposit new rails.

Complete sections of track – rails and crossties – may be prefabricated and laid in the track by mechanical means.

Rail-grinding machines run over the track to even out irregularities in the rail surface.

Track-measurement cars can record all aspects of track alignment and riding quality.

Detector cars move over the main-line tracks at intervals with electronic inspection apparatus to locate any flaws in the rails.

The mechanization of track maintenance has caused a technological revolution comparable to the development of the diesel locomotive and electrification. Precision of operation has gained much from the application of electronics to the measuring and control devices. In Europe, highly sophisticated railroad maintenance equipment has come into general use.

With the XX century the railroad reached a high level of development. Railroad building continued on an extensive scale in some parts of the world, notably in Canada, Russia, China and Africa. But in many other countries construction declined until the second half of the century. Then it was revived, first by the demand for new city transit railroads or the expansion of existing systems and from 1970, by the creation in Europe and Japan of new high-speed intercity passenger lines. The technological emphasis shifted to faster operations, more amenities for passengers, larger and more specialized freight cars, safer and more sophisticated signaling and traffic-control systems, and new types of motive power. Railroads in many advanced countries found themselves operating in intense competition with other forms of transport.

In the first half of the XX century, advances in railroad technology and operating practice were limited. One of the most far-reaching was the perfection of diesel traction as a more efficient alternative to steam and as a more cost-effective option than electrification where train movements were not intensive. Another was the move from mechanical signaling and telephonic traffic-control methods to electrical systems that enabled centralized control of considerable traffic areas. Also significant was the first use of continuous welded rails, a major contribution to improved vehicle riding, to longer track life and reduced maintenance costs.

From 1960, the developed world’s railroads, pressed hard by highway and air competition, progressed swiftly into a new technological age. Steam traction had been eliminated from North America and disappeared from Western Europe’s national railroads in 1968. By 1990, steam power had survived only in China, in parts of Africa and on the Indian subcontinent. China switched to electric locomotive manufacture in 1991. Diesel-electric traction had become more reliable and cheaper to run, though electric traction’s performance characteristics and operating costs were superior.

In the second half of the century, new technology resulted in a steady reduction in electrification’s initial cost. Particularly influential was the successful French pioneering of electrification with a direct supply of high-voltage alternating current at the industrial frequency. This stimulated large electrification programs in China, Japan, South Korea, Russia and India. Those railroads already electrified to a considerable extent either kept their existing systems or, with the perfection of locomotives able to work with up to 4 different types of traction voltage – both alternating and direct current – adopted the high-voltage system. Another stimulus for electrification came with the sharp rise in oil prices and the realization of the risks of dependence on imported oil as fuel that followed the 1973 Middle East crisis. By 1990, only a minority of Western European trunk routes were still using diesel traction.

Few industries benefited more than the railroads from the rapid advances in electronics, which has found a wide range of applications from real-time operations monitoring and customer services to computer-based traffic control.

The latest technologies are widely used in the design of high-performance track and vehicles, both freight and passenger, and for the development of high-speed passenger systems to challenge air transport and the huge growth of private auto travel over improved national highways. The cost of maintaining high-quality track is reduced considerably due to the use of a wide range of mobile machinery capable of every task, from complete renewal of a line length to ballast cleaning or tamping, from ultrasonic rail flaw detection to electronic checking of track alignment.

During the 1990’s, new trunk route construction was considerably active in China, India and Russia, where railroads remained the prime mover of people and freight. Increase of existing route capacity by multi-tracking and creation of new lines was essential for expanding industries and socio-economic development.

Between 1950 and 1990, China doubled the route length of its national rail system to some 33,500 miles (54,000 km); a further 1,000 miles of new lines were proposed in the railroad’s 1990 – 1995 program. New routes, some more than 500 miles long, were built primarily to move coal from the country’s western fields to industries and ports in the east.

From 1950 to 1990, Russian Railways increased the route length from 71,000 to more than 90,000 miles. Extensions included a second Trans-Siberian Line, the 1,954-mile (3,130-km) Baikal – Amur Magistral (BAM). Begun in the late 1970’s, and for almost half its length being laid on a permafrost territory where winter temperatures can drop to – 60°C, BAM carried the first trains in October 1989.

In India new trunk route construction continued in the 1990’s.

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Construction of new railroads for high-speed passenger trains was pioneered by Japan. In 1957, a government study concluded that the existing line between Tokyo and Osaka, built to the historic Japanese track gauge of 3 ft 6 in (1.07 m), was incapable of meeting the needs of the densely populated and industrialized Tokaido costal belt between the two cities. In April 1959, work began on a 320-mile (512-km) Tokyo – Osaka railway built with a standard gauge of 4 ft 8.5 in (1.44 m). The line was designed for the exclusive use of streamlined electric passenger trains. Running initially at a top speed of 130 mph (210 kmph), these trains were until 1981 the world’s fastest. Opened in October 1964, this first Shinkansen (New Trunk Line) was an immediate commercial success. By March 1975, it had been extended via a tunnel under the Kammon – Kaikyo Strait to Hakata in Kyushu Island, to complete a 664-mile (1,063-km) high-speed route from Tokyo. A 1973 government plan to construct up to 12 more Shinkansen made no immediate progress chiefly because of economic problems connected with the global energy crisis. However, two further Shinkansen, the Tohoku and Joetsu, were inaugurated in 1982; three more extensions were begun in 1991. Shinkansen top speed has been raised since the opening of the Tokyo – Osaka Line: it is 150 mph (240 kmph) on both Tohoku and Joetsu, and it reaches 171 mph (274 kmph) on one stretch.

Except for its automatic speed-control signaling system, the first Shinkansen was essentially a development of the traction, vehicle and infrastructure technology of the 1960’s. France’s first high-speed line, or Train a Grand Vitesse (TGV), from Paris to Lyon, partially opened in September 1981 and completed in October 1983, was the product of integrated infrastructure and train design based on more than 20 years of research. Dedication of the new line to a single type of high-powered, lightweight train set with in-built traction enabled design of the track with gradients as steep as 3.5%, thus minimizing construction costs, without detriment to a 168 mph (270 kmph) top speed.

The second high-speed line, the TGV-Atlantique, from Paris to junctions near Le Mans and Tours, was opened in 1989 – 1990. It was built with easier ruling gradients, allowing the maximum operating speed to be raised to 186 mph (300 kmph). During 1991, three further TGV lines were being built. The French government approved construction of 14 more lines under a master plan that would extend TGV service from Paris to all major French cities, interconnect key provincial centers and plug the French TGV network into the high-speed systems of the neighboring countries.

They included Great Britain, to which a rail tunnel under the English Channel was opened in 1993. This tunnel railway is directly connected to a new TGV route, but a modern high-speed line from London via the Channel Tunnel to Paris and Brussels would not be completed until the XXI century. The Netherlands government approved plans for new lines to connect its western group of cities with both the Paris – London – Brussels high-speed triangle and the rapid intercity network created in Germany.

In 1991, Germany completed the Hannover – Wurzburg and the Mannheim – Stuttgart rapid-transit lines designed to carry both 174-mph (280-kmph) passenger and 100-mph (160-kmph) freight trains. Further new line construction is under way and planned for Germany’s most heavily trafficked corridor, Cologne – Frankfurt-am-Main, and between Hannover – Berlin.

In Italy the last stretch of a high-speed line from Rome to Florence, designed for 186-mph (300-kmph) top speed, was finished in 1992. The first segment of it had been opened in 1977, but progress was slowed down by severe geological problems encountered in the project’s tunneling. After some controversy over finance, a mixed holding company of the National Italian Railways and European banks was established in 1990 to extend the high-speed line north from Florence to Milan and south from Rome to Naples, and to build a new high-speed west-east route from Turin to Milan and Venice.

In 1992, Spain completed a new 186-mph (300-kmph) line between Madrid and Seville. The line was built not to the country’s traditional broad gauge of 5ft 6in (1.68 m), but to the European standard. It is fitted with the French TGV design trains.

Outside Europe, South Korea and Taiwan were firmly committed to the construction of new high-speed passenger lines at the start of the 1990’s. Lines were planned to run between Seoul and Pusan and between Kao-Shiung and Taipei. Several other countries, including China, had pushed proposals for high-speed intercity projects.

From the 1970’s, such schemes were advanced in the USA, but by 1990, the only state close to overcoming all political, financial and environmental problems was Texas. A private enterprise consortium was established by the High Speed Rail Authority to develop the first Dallas – Houston segment of the Dallas – Fort Worth – Houston – San Antonio – Austin network based on the TGV technology. The line is designed for the top speed of 200 mph (320 kmph).

In the 1990’s, the Quebec and Ontario governments of Canada were studying the feasibility of a private enterprise proposal to construct a TGV-based, high-speed system connecting the cities of Quebec, Montreal, Ottawa and Toronto.

In the last quarter of the century, the gulf between the technologies and efficiency of the industrialized and developing nations’ railroads was widening. In some African countries the national railroads were close to collapse because of the lack of adequate funds for their maintenance, renewal and construction.

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