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Chapter

AMERICAN RAILWAY ENGINEERING AND MAINTENANCE OF WAY ASSOCIATION

Practical Guide to Railway Engineering

RailwayDevelopment 1-1

©2003 AREMA®

AREMA COMMITTEE 24 - EDUCATION & TRAINING

Railway Development

Prof. Don Cleveland, P.E. (Retired) University of Michigan Ann Arbor, MI 48103-6141 [email protected]

Robert R. Morrish, P. Eng.(Retired) Canadian Pacific Railway West Vancouver, BC. V7T 1P5 [email protected]

John F. Unsworth, P. Eng. Canadian Pacific Railway Calgary, AB. T2P 4Z4 [email protected]

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Railway Development 1.1 Introduction History “Ring Out, oh bells. Let cannons roar In loudest tones of thunder The iron bars from shore to shore Are laid and Nations wonder”

T

his quote from the May 11, 1869 The Chicago Tribune celebrated the completion in Utah of the first transcontinental railway connection in North America. By 1885 the Canadian Pacific completed the first single company transcontinental line and the Atlantic and Pacific were also first linked in Mexico in the 19th century. The exciting impact of a technology that reduced a sixmonth to a six-day trip can hardly be imagined today. In the lifetime of anyone reading this, we have seen nothing with the impact on all aspects of life as the development of the railway. Only 44 years earlier on October 27, 1825 George Stephenson’s steam locomotive, “Locomotion Number 1” hauled a 90 ton load consisting of 36 cars carrying more than 500 passengers and some freight at a sustained speed of 12 mph along the Stockton and Darlington Railway in northern England. This was the culmination of decades of imagination, promotion, engineering and experimentation. What is a railway? A railway can be defined as an engineered structure consisting of two metal guiding rails on which cars are self-propelled or pulled by a locomotive. In his book John Armstrong defines a railway as: “A railroad consists of two steel rails which are held a fixed distance apart on a roadbed. Vehicles, guided and supported by flanged steel wheels and connected into trains, are propelled as a means of transportation.” Webster’s Dictionary (1986)

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defines a railroad as “1. A road laid with parallel steel rails, along which cars carrying passengers or freight are drawn by locomotives, 2. A complete system of such roads, including land, rolling stock, stations, etc. 3. The persons or corporation owning and managing such a system.” The terms railway and railroad are sometimes used interchangeably. However, for this book, railway will generally refer to the track and other closely associated items, i.e., signals, crossings, bridges, etc. Railroad will be used where the usage connotes the bigger system. In commencing a railway engineering career, you are joining many fellow workers in a complex and increasingly coordinated activity that is an integral part of any civilized society. About one-seventh of the workers in advanced economies are involved in some phase of transportation. Transportation, the movement of persons and goods, of which railroading is a large and vital part, is tied in with the location and magnitude of all kinds of human activity which depend on the timely availability of quality goods and services. This ranges from the necessities of food and fuel and work to leisure pursuits. Many of you will be considered as transportation engineers specializing in railway engineering (not operating trains). We can define railway engineering as that branch of civil engineering involved in the planning, design, construction, operation and maintenance of railway land facilities used for the movement of people and goods serving the social and economic needs of contemporary society and its successors. The complete railway engineer is active in all aspects of civil engineering practice, surveying, geotechnics, hydrology, hydraulics, environmental and sanitary and structural design as well as construction technology. You will frequently encounter the word “mode” in your railway practice. A mode of transportation is no more than a particular type of transportation defined in enough detail for the purpose at hand. It can be as general as the medium through or on which transportation takes place; for example, air, sea and land modes. The walking or pedestrian mode involves the moving human. The public transportation mode includes those systems such as rail commuter lines and public bus and taxi service. Often, far more detailed descriptions are needed for effective analysis, communication and understanding. The railway mode is a type of a land transportation mode as defined above. The light rail transit mode is a further more specifically defined type of rail service, typically today an urban, electrically powered system operating on its own right of way with intersections with intersecting public streets. Other terms used in railway engineering are listed and defined in the Glossary found at the end of this Manual.

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1.2 Determinants of Transportation Development Transportation is rarely an end in itself except for those modes designed for the enjoyment of passengers such as roller coasters. With these exceptions, transportation serves only to provide a linkage between separated locations. Its usefulness can be measured by the way in which this service impacts the: §

Time needed to move from an origin to a destination.

§

Departure and arrival time.

§

Reliability of moving the actual or potential demand for movement.

§

Safety and comfort dimensions are also highly important.

Transportation of some sort beyond the human leg has always been needed since only in the tropical paradise of a small Pacific Island could food, lodging, individual and social needs be met. Society places a value, a willingness to pay, on the availability of something at a location at a particular time. If that good can be purchased at another location and if the total of that cost and the transportation cost is less than what the buyers will pay, then there is an advantage to be gained from providing the transportation service. Goods in Baltimore have no value to residents of Philadelphia. Making them available in Philadelphia gives these goods a value. For example, an 1854 analysis of moving corn from an agricultural area in the USA to a potentially expanding market place by horse and wagon equaled the cost of the corn after a distance of only 165 miles. The same analysis showed that the railway technology of that time could extend this distance by a factor of ten to more that 1,600 miles. An ideal transportation system would have no costs, take no time, be available at all times, be capable of moving as little or as much demand as exists, do no damage to the item being moved, meet comfort needs, be safe and be completely reliable. It is clear that no mode can meet these ideals and that the components which contribute to the potential of a mode depend on technology, human performance, capital availability, organization, governmental support, regulation and interference, competing entities in the same and other modes of travel and undoubtedly other factors. Providing modern forms of transportation requires large initial investments and continuing operating costs. All successful improvements in transportation are based on demonstrating that the benefits or utility, results of improvements in service, exceed the costs. These benefits can come from technological improvements, from institutional opportunities flowing from relaxed constraints and from the availability of capital investment. We will now consider some examples of the development of

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North American transportation innovations, which contributed immensely in benefits and resulted in great societal changes.

1.3 Pre-railway Transportation in North America Through the fifteenth century, Native Americans relied on movement by water wherever possible. Light and strong canoes constructed of wood and animal skins could move up and downstream and be easily portaged between river headwaters and lake access points by human carriers. Movement by land was limited to human power with goods being carried or dragged necessarily short distances. This type of transportation system appears to have been in place for hundreds of years and shaped all aspects of native life. (See Figure 1-1)

Technology

Drag

Horse

Figure 1-1 Primitive North American Transportation

The first “technological” change was the 16th century introduction of the horse by the Spanish settlers of Florida and the Southwest. Some of these horses escaped and were quickly recognized by the natives as increasing their choices in all aspects of living, hunting, moving, warfare and the demands and pleasures of daily life. (The impact of

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the horse in these primitive economies was probably as great as that of the railway in the 19th century.) The natives needed no assistance in mastering control of this mode of transportation and soon became expert in the care and use of horses as person carriers as well as goods movers. Eastern Native American tribes did not have the advantage of ready access to horses and their civilizations, which were close to the immigrant European settlers, did not have time to benefit from this mode before they were overwhelmed by westward expansion. European immigrants introduced the use of the wheeled cart to North America. While dry natural earth surfaces used by foot and horse traffic are satisfactory in dry weather they quickly deteriorate into bumps and ruts from rain and frequent wheeled vehicle traffic. The effective use of the horse-drawn wheeled vehicle for many uses depended on the development of spring systems and a suitable surface. Consequently, the first function is to pave the surface to provide a continuous smooth, load-bearing and weatherproof surface. Of course, Europe was laced with the still suitable 1,500 year old, immensely costly to build, often 40 feet wide stone surfaced Roman road network. However, these massive (often 5-foot deep) structures were not economically feasible in a young society unable to allocate capital for material and labor (free or slave) to such an activity. It was in the late 18th century that modern concepts of road building began to emerge in Europe. It was realized that a proper surface rests on a base of rock aggregates, which distribute the loads from the wheels to the subgrade below as well as draining water away from the subgrade. Since massive quantities of such materials are needed in a meaningfully extensive road system, such a road structure system must be economical of materials and construction and maintenance effort if they are to consistently meet the needs of traffic. Where built with these principles in mind, it became possible to move persons and goods on land with horse drawn wheeled vehicles supplanting the pack horse or human. In the United States, there was an extensive development of toll roads and bridges and Federal support for a road-building program was initiated before 1800. The generally dominant mode of transportation before and even after the emergence of the science and engineering of improved road surfaces remained of course, the water mode. Cities of any size were ports on oceans or navigable rivers. DaVinci engineered a successful lock system in the 16th century and by the 18th century the European development of an extensive canal system was followed by a similar movement in North America. Investments in canals in the Eastern United States were extensive and there was much governmental as well as private support for this early in the 19th century. Interestingly, these investments peaked just as the railway explosion decade of the 1830’s began. Although slow, the quantities movable by barge were relatively large and operating costs were low.

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1.4 Physical Determinants of Land Movement Moving a vehicle on and/or through a medium, land, sea or air, requires overcoming resistances to motion. For land vehicles, the total resistance (pounds or Newtons) is a quadratic function of the vehicle’s speed. There is an initial constant resistance to which is added a term, which is linear with speed, V. And another term captures primarily the effect of the air resistance, which has been found to increase with the velocity squared, V2.. The resulting relation is R = a + bV +cV2 The shape, frontal area and sides of the vehicle or train are the primary determinants of the constants associated with this air resistance. The overall effect of air resistance on useful haulage comparisons among ground modes operating at the same speed is not great. The resistances between the vehicle contact point and the surface of the roadway are very different for rubber-tired wheels on any kind of surface and metal wheels on metal rails. Typical results for a motor truck and a train can be expressed in g’s in the following table: Speed, V 10 mph

60 mph

Railway

0.001 g

0.024 g

Truck

0.009 g

0.090 g

This significant advantage of railways in overcoming resistances can be used in several ways. The train can operate at higher speeds, carry more payload, reach higher elevations easier or use less power. (See Figures 1-2 and 1-3) In the long run it is the cargo capacity that counts most in comparative energy requirement analyses. Morlok presents a comparison of several transportation modes, using as a measure of effective performance, the combined speed and size of the cargo being moved in a day, this being expressed as ton-miles per day. For example, a human can carry 100 pounds 20 miles in a day, producing one-ton mile. Both the pack horse and wheelbarrow can produce 4 ton-miles/day, a horse cart on good pavement 10, a fully utilized truck 20,000 and a long haul train more than 500,000 net tonmiles/day. Clearly, moving large quantities of freight long distances along the same route favors the railway mode. Table 1-1 shows these findings published before 1840.

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There are several forms of motive power, which are used to overcome resistances to motion along a railway route. The primary source of energy for movement comes from converting fuel to heat and then to propulsive force in the locomotive. However, there are also the accelerative force of gravity on downgrades, the stored energy manifested in the speed of movement of the large mass of a train and energy in its many rotating parts. When one considers the available designed horsepower of the railway locomotive, the barge power plant, or the engine of a truck as well as the weight of the vehicle needed to handle cargo, one finds that the slow moving barge requires only 0.2 hp/net ton carried, the railway and pipeline 2.5 and the truck 10. However, at higher speeds, the railroad becomes, by far, the most economical mode of transportation.

Figure 1-2 Model Resistance

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Figure 1-3 Train Resistance Table 1-1 - Early Studies of Resistances and Transportation Efficiencies

Source: Day; 1831 Resistive Force Resistance Lb. * g's

Type of Surface

Ton miles Net ton miles Moved/day Moved/day

Cost/net Ton-mile

Gravel Road

147

.063

21.4

16.1

5.23 c

Broken Stone Rd.

46

.020

68.5

51.4

1.64 c

Well made pavement

33

.014

95.4

71.6

1.17 c

Tramway

24

.010

133.9

100.5

0.84 c

Railroad

9.8

.004

321.4

241.1

0.35 c

* Weight of wagon is 2,100 pounds

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1.5 North American Railway Development and Impacts Modern railway transportation became possible with the invention of the steam engine by James Watt in the late 18th century. This multiplier of the ability of man to harness energy initiated the industrial revolution. In the transportation field, the steam engine was first used in ship transportation to give more flexibility to upstream river and coastal travel and was immediately seen as a possible portable motive power source for land vehicle transportation. (See Figure 1-4) Entrepreneurs soon began to push for necessary governmental approvals to meet the need for land for routes, and both private and governmental sources were tapped for capital. The energy saving advantages of a solid rolling wheel on a hard supporting surface for moving goods were used at least as early as the 17th century. There were fixed and relatively close origins and destinations, coupled with large amounts of material to be moved. Such situations were found in moving coal and ore within the mine and from mine heads to ship side or destination. The propulsion of the carts used for such movement was often gravity with horses used to back haul the empties back to the mine. These railway forerunners were first surfaced with wooden rails on stone, then with these rails covered with iron strips. Of course, it was natural to attempt to develop a physical means of reliably guiding the vehicle. So-called fixed guideway systems existed in some Roman roads where rock roads with longitudinal constant separation (gauge) grooves kept wheeled vehicles fitting these grooves on the desired path. The flanged wheel with the flanges on the inside of the rail was soon discovered to be the best way of preventing undesirable lateral movement of the wheel associated with forces produced while traversing a curve. Trevithick, an English colliery engineer, put a steam engine on guiding wheels in the early 1800s. There were active American development attempts well before Stephenson’s 1825 successful demonstration. Between 1786 and 1804 Evans and others had conducted demonstrations. John Stevens ran a successful rail vehicle in 1810 and advocated the chartering of railways rather than canals in 1815. He was ignored. Of course, Robert Fulton’s 1807 steamboat running upstream on the Hudson from New York City to Albany at an average speed of 5 miles per hour convinced even more skeptics. (See Figure 1-5) Within five years of Stephenson’s 1825 English demonstration, the railway transportation mode in North America had a vibrant beginning. The first track in the United States was put in service in 1830 on what was to become the Baltimore and Ohio Railway. (See Figures 1-6 and 1-7) The 1830’s were exciting for railway development throughout the world. By 1836 railway construction was underway in 14 states and 1,000 miles had been completed by 1840. There was a 163-mile continuous section in Pennsylvania and 262 locomotives were already in service.

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Side Paddle Paddle

1807 African Queen

Screw

Figure 1-4 Early Steam Applications in Watercraft

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Flange Out

Grooved

Haunch

Ringwalt

Figure 1-5 English Railways and Freight Cars, as Illustrated in Strickland’s Report, 1826

Railways quickly became a major factor in accelerating the great westward expansion, as well as tying the older eastern population and industrial centers together, by providing a reliable, economic and rapid means of transportation. As additional lines were built, they facilitated the establishment and growth of towns in the West. Except for the trip from farm to railhead in town, the poor roads and limited canals became irrelevant. The Federal government and states encouraged and provided financial support through land grants and loans, which were paid back with reduced rates for half a century. Since the first railways, there have been many improvements in all aspects of railroading. For example, the development of the iron flanged “T” rail was achieved by 1840. (See Figure 1-8 for an early track section) Until mass steel making was developed, there was a continuing controversy between the use of malleable iron vs. cast iron for rail. By 1840 wooden ties kept in place by ballast stone had replaced simple stone surface support.

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Figure 1-8 An Early Track Section - Source: Day

1.6 Developments of the Twentieth Century The railways peaked in 1920 when there were 250,000 miles in service in the United States. Following the growth in motor truck usage and the completion of the Interstate Highway System, this had declined to 155,000 miles in 1983. In the first 60 years of the twentieth century, there were relatively few, obviously better, but not widely adopted, technological changes in the railway industry. Notable were improvements in the development and wide adoption of the diesel-electric locomotive and signal systems and train control. This was not for a lack of engineering and scientific advances, but a feature of the regulatory and capital investment climate. The explosion in the use of the automobile and truck contributed to a decline in adopted innovations until inter-city rail passenger travel all but disappeared. Since then, the stability of the transportation market, regulatory constraint loosening and the incredible advances in electronics have led to a host of innovations universally adopted and contributing to development of a more efficient rail mode. A partial list of some of the most important of these follows: §

Continuously Welded Rail (CWR) 1/4 mile long on large parts of the rail network.

§

Concrete tie usage expanding dramatically.

§

Precast bridge segments.

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§

Geotextile applications in subgrade improvement.

§

Double tracking major lines to achieve capacity increases as well as economically justified realignments.

§

Increases in clearances to accommodate larger cars.

§

Highway grade crossing eliminations and protection upgrades.

§

Elimination of unneeded track by major railways and the emergence of the “shortline” railway company handling many of these low volume lines profitably using low cost approaches.

§

Intermodal terminal and handling technology and the development of new yards.

§

High-speed rail development, particularly in foreign countries.

§

The elimination of steam locomotion and advances in diesel-electric propulsion to include AC traction systems as well as propulsion braking systems.

§

Development of specialized cars and incorporating them into intermodal operations including widespread use of containers and container handling equipment.

§

Adoption of long known improvements in bearings used in freight cars.

§

Changes in national and urban area rail passenger transportation to include light rail transit systems and the formation of public agencies with responsibilities in these increasingly important areas.

§

A concern with environmental impacts of all types.

§

Heightened concern with employee and public safety.

§

Better scheduling of operations to satisfy the need for more reliable time sensitive transportation to support “just-in-time” inventory control.

§

Downsizing employment in the industry and the greater use of contractors and consultants.

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1.7 Development of Canadian Railways The railway has had a tremendous impact on the growth and location of economic activity in this enormous country. Its size, climate and the immense Rocky Mountain range pose challenges to any ground transportation system. The explosion of railway activity in the first half of the 1830’s was not matched in colonial Canada. There, initial development was delayed a few years, among other reasons, by the already ongoing investments in canals and waterway transportation in the eastern populated Upper and Lower Canada. There had been precursors to railways before that time. As in Britain, moving stone from quarries short distances to building sites or to water transportation terminals on tracks with horse drawn cars took place in Canada. The French capitol fortress Louisburg on Cape Breton had stone moved in this way about 1720. A few years before railway development, a steam-powered winch was used to pull cars on tracks carrying materials used to construct Quebec’s Citadel. Coping with waterways frozen five months per year and poor roads, political and commercial figures soon saw the potential benefits of a railway system. The first Canadian railway, the Champlain and St. Lawrence, linking the St. Lawrence and Richelieu rivers, began passenger and freight service in 1836, three years after President Andrew Jackson rode as a passenger on the Baltimore and Ohio Railway. Three years later the 6 mile long Albion Mines Railway, linking that mine to a pier near Pictou, Nova Scotia, began operation. The St. Lawrence and Atlantic Railway, linking Montreal and Portland, Maine, and providing a year round ocean outlet for Montreal, was privately but inadequately financed by local and English sources. The Guarantee Act of 1849 provided federal support in the form of a partial interest guarantee on half the bonds, and this line was then completed in 1853. The Great Western Railway linking Niagara Falls with Windsor near Detroit was completed a few months later. This line had also obtained a loan from the government. Prior to confederation in 1867, the most ambitious project was the Grand Trunk Railway. It was intended to tap the needs of the Great Lakes area as well as prairie Canada, and ran from Sarnia at the foot of Lake Huron to Montreal, being finished in 1860. The tunnel linking Sarnia to the United States was completed in 1891 and a new tunnel was completed in 1995. The effect of the railways in locating and stimulating growth of newer urban centers was notable. Toronto, Winnipeg and Vancouver are examples.

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The first Canadian built locomotive was manufactured in Toronto in 1853. Canadians invested in making almost everything used by the railways. In many smaller communities, the railway was the largest and dominant employer and its facilities became the focus for the development of the community’s commercial, industrial and residential properties. The first successful rail car braking system and the rotary snowplow were developed by Canadians. Fleming devised the time zone system as a response to difficulties in coping with innumerable local times along the rail lines. Formation of the Canadian nation in 1867 emphasized the need for railway transportation ties. Authorization of the construction of the Intercolonial Railway was written into that year’s Constitution Act. This railway was owned and operated federally being financed primarily by British loans backed by imperial guarantees. It was completed in 1876 and linked the Maritimes with the main population centers. In 1871 British Columbia joined the nation with the promise of a rail connection to eastern Canada. President Lincoln had signed the American Transcontinental Railroad Authorization Act in 1862 and transcontinental service in the United States was completed in 1869. The Canadian government, wishing to connect western Canada with the east, signed a contract with the Canadian Pacific Railway (CPR) in 1880. The CPR received cash, land, tax concessions, and 20 years of protection from competition on the prairies. The CPR was built through the Rockies, in a still admired engineering and construction feat led by William Van Horne, and was completed to Vancouver in 1885. A passenger train moved from Montreal to the Pacific in the summer of 1886. Population growth in the prairie west after 1900 strained the CPR capacity and another phase of expansion began. The Canadian Northern Railway added links to Regina, Saskatoon and Edmonton. There were other notable efforts including the Grand Trunk Pacific, constructed between 1906 and 1914 using the Yellowhead Pass to Prince Rupert, BC. Overbuilding and World War I caused a crisis. Immigration ended and capital became harder to secure. In May 1917, nationalization of all but the CPR and American lines was recommended by a royal commission. The Canadian National Railways, CN, was the name authorized and its organization was completed in 1923. Several lines were extended northerly in the following decades. For example, in 1954 the Quebec, North Shore and Labrador Railway accessed the gigantic iron-ore deposits in that region. The Great Slave Railway opened in 1965 between northern Alberta and the Northwest Territory at Hay River. Other important milestones included the introduction of the diesel-electric locomotive by the CN in 1928. Full dieselization was reached on the CN and CPR in 1960. Long distance passenger service was provided by VIA Rail in 1978. In 1984 the CPR pioneered North American use of AC traction for locomotives. The CN was privatized in 1994.

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James Marsh, writing in the Canadian Cyclopedia (this text adapted in part from his Railway History article), stated “the building of the Transcontinentals, perhaps provided for Canada the closest approximation of a heroic age.” Readers are encouraged to turn to Appendix “A” to read the excellent article prepared by Robert Morrish, retired Chief Engineer of the Canadian Pacific Railway entitled “Applied Science for Railway Tracks – 1946 to 2002” to gain, not only an understanding of the development of maintenance processes in Canada, but in all of North America as well.

1.8 Mexican Railway Development As in the United States, the development of railways vastly affected Mexican commercial expansion and national progress. As early as 1837, a federal decree granted a concession for a railroad from Mexico City to Vera Cruz on the Gulf Coast. However, nothing came of this. The first of the large railways, the Mexican Railway, finally began this project in 1867 with the delay being due to national political instability. The line was completed in 1873. The resulting advantages were so great that a connection with the United States became imperative and capital was readily made available for railway access to a mountainous country without navigable rivers or canals. The Central, formed in 1880, served the backbone of the country traversing the ridge of the plateau and the flattened crest of the Mexican Andes from Mexico City to the Rio Grande, with branches going from intermediate points to both the Atlantic and Pacific coasts. The first train crossed the border at El Paso, Texas in 1882. The National, authorized in 1880, was a long narrow gauge railroad with a total length of 2,000 miles, which ran from Mexico City west to the Pacific and entered the Unites States at Laredo, Texas. It created a direct link from New York to Mexico City, a distance of almost 3,000 miles. The Morelos, another narrow gauge line, crossed the country from Vera Cruz to Acapulco. It was entirely developed with Mexican capital, engineering and labor. A portion was opened in 1881 and one week later a bridge foundation was washed out, resulting in the loss of life for 200 passengers. Following the 1914 revolution, the Mexican Constitution mandated that the Federal Government own the only still surviving railroad, FNM (Ferrocarriles [iron horse] Nacionales de Mexico). As has often been the case, governmental operation led to shortcomings in efficiency, reliability, service and competitiveness. Even with Mexico’s poor highways, FNM carried only 15% of the nation’s freight in 1995. In 1995, a privatization of the rail system was authorized and by the end of the century, seven separate regional rail systems had been sold by public auction. Franchises can extend as long as 100 years.

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The largest and most heavily used (46% of tonnage) system is the Northeast Railroad or TFM, connecting Mexico City with Laredo, Texas (> 50% of US trade crosses here). It has branches to Brownsville, Texas and the Gulf and Pacific coast ports, operates on 2,600+ miles of track and began operations in 1997. Forty-nine percent ownership is held by KCSI. The second largest system, partially owned by the UP, Ferrocarril Mexicano, operates about 5,000 miles of track in northwestern Mexico with connections to the southwest United States. Mexican rail transportation is highly competitive with trucks as shipments are generally much shorter than in the United States. The absence of intermodal facilities and customs clearance problems is a current challenge.

1.9 Institutional Controls A particular institutional and usage challenge was placed by the fact that before the railway, there was no transportation system able to carry various types of traffic combined with single ownership and control of the way, cars and propulsion system. It is clear that significant efficiencies were obtained when this occurred, although early systems with ownership and control of the road in one hand and all cars and power owned by several private entities were tried. Federal control of many aspects of railway operation and service has been a feature since their founding. Until 1980 railways were the most and longest regulated American industry. The Interstate Commerce Act was passed in 1887 to rein in monopolistic practices and provide fair access at reasonable rates to shippers. In the 1976-80 period, it was finally recognized that the need for railway regulation in all aspects of operation was no longer necessary and the Staggers and other Acts freed the marketplace somewhat. Labor agreements between the railways and the brotherhoods have improved flexibility of operations. There were no important railway mergers between 1910 and 1955. Since 1980, three-quarters of the railways have been merged out of existence. Intercity passenger movements have been in the hands of heavily subsidized AMTRAK for more than 30 years. AMTRAK operates trains on private railway tracks under agreement. AMTRAK also operates a highspeed service on its own ROW in the Boston-New York Northeast Corridor. Current regulatory bodies include the Federal Railway Administration, FRA, in the United States and Transport Canada. OSHA and Labor Canada have a strong say in workplace safety. With the mergers and capital analyses, a large civil engineering force at each of the railways, capable of designing, constructing and maintaining the way has virtually disappeared. Many of these activities are now performed by consulting engineers and contractors. This Practical Guide to Railway Engineering is an attempt by

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engineers with decades of experience to share with engineers new to railway engineering, much of the knowledge they have acquired over their professional careers.

1.10 History of Railway Bridge Engineering William Worthington of the Smithsonian Institution presented a historical survey of American railway bridges at the 1991 meeting of the American Railway Bridge and Building Association. He covered 19th and early 20th century developments thoroughly and this section summarizes part of his presentation. Displayed in the National Museum of American History next to the John Bull, Stephenson's steam locomotive, which ran in New Jersey in 1831, is the nation's first cast and wrought iron railroad bridge, built in 1845 by Richard Osborne for the Philadelphia and Reading RR. This bridge was in use until 1901. Of course, stone was the preferred bridge material when promptly and economically available. However, stone construction was slow and expensive. Fortunately, the continent was covered with forests and wood was the best solution where available, despite its structural limitations and fire hazard. Many stone bridges were constructed and a large number of these 19th century masonry bridges are still in use. Using wood, American railway bridge designers soon played a lead role in bridge truss design. Almost one wooden bridge design patent was issued each year in the first half of the 19th century. Among those were the Pratt and Howe truss designs, which could be used with both wood and metal structures. Although their life was limited, wood bridges made it possible to extend a line quickly and cheaply. A key wooden structure, making it possible to keep railway grades low, was the timber trestle. It could be constructed quickly and would have a life of at least 15 years. Numerous trestles were ultimately converted to fills by hauling material to the site cheaply by train. Worthington believes that the 1892 Two Medicine Bridge on the St. Paul, Minneapolis and Manitoba Railway is perhaps the ultimate example of the 19th century wooden bridge builders' art. It was 750 feet long and 210 feet high. Of particular interest is that by that time steel was the material of choice. But location, cost and time constraints dictated a wooden trestle at this location The distinctive Bollman truss, incorporating elements of truss and suspension bridge design, was used in the 1850-70 period to replace many of the first generation wooden bridges, particularly on the B & O RR. As in other parts of the world, there were failures. One notable 1887 accident, costing 23 lives, occurred on the Boston and Providence RR. Before the failure, loose nuts

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had occasionally been found below the bridge. The failure was traced to the fracture of two hangers suspending the track structure from the top chord. They were poorly designed and of inadequate strength and the fracture had existed for a considerable time. Theodore Cooper, father of the bridge loading analytic system still in use, characterized this as "An abortion in design and construction in which no engineer had any part." Perhaps the most unusual American railway bridge of that century was the Niagara Gorge suspension bridge designed and built in the 1860's by John Roebling, designer of the Brooklyn Bridge. The only feasible construction technique available was the suspension type, which with stiffening could accommodate the light railway fleet of the day. Rail traffic used the upper deck and vehicular movements were on the lower level. Despite limiting rail traffic to 5 mph the deck truss flexed somewhat. In 1869, Mark Twain observed that when crossing it you: "Divide your misery between the chances of smashing down 200 feet into the river below and the chance of having the railroad train overhead smashing down on you. Either possibility is discomforting taken by itself, but mixed together they amount to positive unhappiness." One of the most significant steps taken in bridge construction after the Civil War was the application of the ancient method of cantilever construction. During the 1870-90 period, steel manufacturing developments created a market for this material and the steady supply of reasonably priced products in many shapes permitted construction of all-steel bridges. As bridges became stronger, more powerful and heavier, locomotives required even stronger bridges. For example, on the B&O RR, the heaviest engine in 1865 weighed 91,000 pounds, while in 1890 it had increased to 133,00 pounds and another 25 years later in 1915, it reached 463,000 pounds To accommodate these increased weights, speeds on older bridges had to be limited to an unacceptable 15 mph and bridge replacements were necessary. The first all-steel bridge in Glasgow, MO was replaced in 1901 after only 22 years of service. Twentieth century bridge design exhibited a sturdy sameness. Smaller bridges were likely assembled of Pratt or Warren designs. Some longer and higher bridges were built, culminating in the high Huey P. Long Bridge over the Mississippi River at New Orleans.

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1.11 New Technology – Bridge Developments in the Last Twenty Years1 Innovation and technology development over the past twenty years has focused on the challenges related to the maintenance of existing railway bridges; as well as the design and construction of new bridges required to improve railway infrastructure safety and reliability.

1.11.1 Existing Railway Bridges: Inspection and Assessment Like many railway-engineering personnel, the railway bridge infrastructure is aging. The existing bridge infrastructure is also being subjected to heavier axle loads and increased traffic volumes. The planning and design work associated with the assessment and maintenance of existing railway bridges is an engineering challenge requiring an understanding of the modern railway live load regime and the behavior of railway bridge structures. Inspection of railway bridges has improved thorough the use of on-track bridge inspection vehicles and various non-destructive testing techniques that allow the engineer or inspector to obtain a thorough understanding of existing bridge conditions in a safe manner. There have also been many bridge access safety improvements in recent years such as the provision of fall protection lifelines and walkways on bridges. Modern railway live loads are of large magnitude and frequency. While heavy locomotive weights have not increased substantially since the 1920’s, car weights have increased considerably. Modern car axle loads are of the same magnitude as locomotive axle loads. This means that existing railway bridges are subjected to many more applications of heavy axle loads than envisaged at the time they were originally designed and constructed. The resulting increased stress ranges and greater number of cycles of load precipitates fatigue damage accumulation in some bridge components. Recent developments associated with structural analysis, stress-life fatigue behavior and crack behavior, enable the railway bridge engineer to assess the safe fatigue life of railway bridges. The railway bridge engineering community has been instrumental in developing improvements in the stress-life testing of components with characteristics typical of 1

John Unsworth, Canadian Pacific Rail

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existing steel railway bridges. Railway bridge engineers have also been leaders in the use of linear elastic fracture mechanics in conjunction with acoustic emission monitoring and other non-destructive techniques for fatigue life assessments. Modern computer programs have brought a host of analytical tools, such as threedimensional structural analysis, to the engineer’s desktop. Modern non-destructive testing techniques, such as strain measurement and ultrasonic testing, can be used with advanced structural analysis to gain a better understanding of structural behavior of components and details. Furthermore, recent developments in railway bridge strength rating methods have allowed for strength rating calculations based on load regimes on bridges over an indefinite period of time and at infrequent intervals. Innovative techniques and materials strengthened with fiber reinforced composite materials and cable post tensioning have been used to strengthen railway bridges. Bridge engineers have been able to develop bridge replacements and/or rehabilitations on a project and program basis through the use of computer based bridge management inventory and condition rating systems. These developments have enabled railway bridge engineers to propose appropriate and cost-effective rehabilitation and strengthening of existing structures to maximize the life of the structure.

1.11.2 New Railway Bridges: Materials, Design, Fabrication and Construction Replacement of railway bridges becomes necessary when economical rehabilitation and strengthening are not feasible. To construct safe, cost-effective and maintainable railway bridges, engineers have adopted recent technology developments in the areas of analysis, materials, design and fabrication. The computer is playing an important role in the analysis of structures. However, while sophisticated computer analysis is available and used by modern bridge engineers, it is not a substitute for an understanding of structural behavior. Many experienced bridge engineers may not know their way around a computer keyboard, but have an intuitive understanding of structural behavior that electronics technology cannot completely replicate. However, for experienced bridge engineers, an improved understanding of the load and force distribution is available through advanced computer structural analysis. Over the past 20 years railway car axle loads have increased by more than 30%. Investigation into the dynamic stresses imposed on railway bridges and the stress-life behavior of bridge components have permitted improved engineering designs. Longitudinal traction loads due to new AC high adhesion locomotives have also been identified and included in modern railway bridge designs. Improved understanding of serviceability issues such as fatigue, deflection, vibration and concrete crack control

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under heavy axle load regimes has been facilitated by recent railway bridge engineering research efforts. Design methods such as limit states methods for concrete structures have improved the reliability of concrete bridges. Modern seismic deign methods based on performance limit states have been developed in recent years. Composite steel-concrete structure design has been developed for railway bridges to produce economical, easily constructed and maintainable ballasted deck structures. Material improvements have been considerable over the past two decades. Alloyed weathering steels that are resistant to atmospheric corrosion with good fracture toughness and high strength (yield strength up to 70 ksi and 100 ksi) have been used in the design and construction of new railway bridges. High strength concrete has made possible the efficient design of heavily loaded railway bridges with improved durability. Prestressed concrete has also been utilized for short span construction. Economical concrete box girder and slab bridges using precast prestressed and cast-in-place posttensioned technology have been used for ballasted railway bridge construction. Precast segmental construction has provided for cost effective substructure and superstructure replacement with minimum interruption to traffic. Technology development for the economic replacement of existing railway timber bridges has involved developments such as prestressed concrete rehabilitation and replacement components. Welding technology improvements have enabled the economical construction of steel bridges with improved fatigue characteristics. Computerized shop fabrication has improved fabrication accuracy and efficiency. In recent years, CWR has been installed on both open and ballasted deck bridges due to recent work on the understanding of effects of bridge movements due to thermal expansion, particularly on open deck type bridges. Protective coatings and paint materials and methods improved considerably over the past 20 years. Zinc rich paints, epoxy and polyurethane paint systems for shop painting and overcoating have been developed. It is expected that technology improvement in the area of railway bridge engineering will develop at an increased pace due to the need to maintain, rehabilitate and reconstruct an aging railway bridge infrastructure.

1.12 Trade Journals Currently one can keep current by reading the following monthly magazines: Railway Age, Progressive Railroading and Railway Track and Structures. AREMA Proceedings are an important source of current advanced practices.

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1.13 Other References In preparing this overview, reference has been made to the 1839 2d. edition of James Day’s A Practical Treatise on the Construction and Formation of Railways, London, and J. L. Ringwalt’s self-published in Philadelphia in 1888 Transportation Systems in the United States. A modern transportation text used in many university courses is Edward Morlok’s, Introduction to Transportation Engineering and Planning, McGraw-Hill, New York. Thomas F. Hickerson’s, Route Location and Design, McGraw-Hill presents many of the geometric problems associated with railroad surveying practice. Part of the material on Mexican Railways is adapted from a recent article by Attorney Richard A. Allen of the Zuckert, Scootl and Rasenberger law firm. William Worthington in the 1991 Bridge and Building Proceedings presented an historical survey of railway bridge and building history.

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