LIGHT RAIL VEHICLE DESIGN CHARACTERISTICS - Non-Articulated/Articulated (1 of 2)

Light rail vehicles are built in a variety of designs and dimensions. In almost all cases, they are capable of being operated in coupled trains. Modern LRVs are generally much larger and heavier than their streetcar predecessors and can have axle loads just as large as, or even larger than, so-called "heavy rail" transit vehicles.

Light rail vehicles vary in the following design characteristics:

1. Unidirectional versus bi-directional
2. Non-articulated versus articulated and, for the latter, the location(s) and configuration of the articulation joints
3. 100% high-floor versus partial low-floor (typically 70% or less) versus 100% low-floor
4. Overall size (width, length, and height)
5. Truck and axle positions
6. Weight and weight distribution
7. Suspension characteristics
8. Performance (acceleration, speed, and braking)
9. Wheel diameter and wheel contour
10. Wheel gauge

These characteristics must be considered in the design of both the vehicle and the track structure.

2. Non-Articulated/Articulated
The earliest electric streetcars in the 1880s were four-wheeled single truck vehicles. Streetcar ridership quickly outgrew the capacity limitations of such vehicles, and eight-wheeled double truck streetcars were common by 1900. Often, these larger cars would pull a trailer car for even more capacity. The first articulated streetcars appeared in the United States about the time of World War I, often by splicing together two older single truck cars, and later as three-truck vehicles functionally very similar to high-floor, articulated LRVs of today. The objective of this evolution in vehicle design was to maximize not only passenger capacity but also the number of passengers carried per operating employee since labor costs, then as now, were a high percentage of the cost of transit operation.

That trend has continued up through the present with the result that multiple-section light rail vehicles have reached unprecedented lengths. Today, with the exception of legacy and heritage streetcar operations and three light rail systems that bought new rolling stock in the 1980s, all new and modernized North American light rail systems are using articulated cars with two, three, or more carbody sections. Two-section articulated LRVs, which were the most common design when the first edition of the Track Design Handbook for Light Rail Transit was published, are now being purchased only for those LRT lines that require a 100% high-floor car to match highplatform stations.

The development of LRVs with multiple-carbody sections (up to seven sections in the case of trams purchased in Budapest, Hungary, in 2007) was driven by the same issues as a century ago—carrying more passengers with fewer operating employees. Multiple-carbody vehicles also have fewer motorized trucks per passenger and thereby provide substantial energy savings. Several North American systems are following this trend. Toronto ordered new five-section streetcars in 2008. Dallas Area Rapid Transit, following a trend started in Europe, modified older two-section, high-floor light rail vehicles to add a low-floor center section. New Jersey Transit has investigated adding two additional sections to their current fleet of three-section, 70% low-floor cars.[4]

Where two body sections meet, a turntable and bellows arrangement connects the sections, allowing continuous through passage for passengers from one end of the car to the other. In the case of high-floor LRVs, a single such arrangement, centered over a truck of conventional design, is used to connect two carbody sections. Low-floor LRVs require two such articulations—one on each side of the center truck and center section of the carbody—since there is no room for the turntable above the special trucks required under low-floor cars. This usually results in a very short carbody section at each low-floor truck.

THE OLD AGE OF RE

None of the flooding caused by the river Nile could be compared to the destructive floods caused by the Euphrates and Tigris. Therefore there is no Egyptian myth of the destruction of mankind by inundation. According to this myth Re grows old and feels that his authority over gods and man has diminished. He gathers an assembly of gods and tells them that men are plotting against him. He asks the advice of Nun, the eldest of the gods. Nun advises that the eye of Re, in the form of goddess Hathor, should be sent against mankind.

Hathor is sent. She begins her slaughter and wades in blood. But apparently Re does not desire a complete destruction of mankind so he devises a plan for the making of seven thousand jars of barley beer dyed with red ochre to resemble blood. This is poured out on the fields to a depth of nine inches. When the goddes sees this flood shining in the dawn, reflecting her own face in its beauty, she is lured, she drinks and becomes drunk and forgets her rage against mankind. So mankind is saved from total destruction (So now you know who saved mankind from extinction!).

LIGHT RAIL VEHICLE DESIGN CHARACTERISTICS - Unidirectional/Bi-Directional (2 of 2)

The following are some of the factors that should be considered when evaluating single-end versus double-end light rail vehicles:

• Systems with stub-end terminals at either one or both ends of the line or at any intermediate turnback location will require bi-directional vehicles.

• Bi-directional vehicles with two operating cabs and doors on both sides of the vehicle will cost more than a single-end LRV with only one cab and doors on only one side.

• For slow speed movements in a yard or under an emergency situation, many single-end LRVs have a “back-up controller” in the rear of the car, often hidden behind a panel or under a seat.

• Unless equipped with doors on both sides, single-end LRVs require that all station platforms be located on the same side of the tracks. Having doors on both sides of the vehicle provides the capability of having stations on either or both sides of the track, regardless of whether the vehicle has one operating cab or two.

• Single-end vehicles that have doors on both sides can be coupled back-to-back resulting in a double-end train.

• The choice of single-end versus double-end vehicles may have an impact on how yard and shop facilities are laid out. This in turn will affect the real estate requirements for that facility and hence its location. The yard location in turn may have a direct effect on the system operating plan.

• Double-end vehicles typically have more uniform wear of the wheels since the leading axle on each truck changes at the stub-end terminals. Single-end vehicles often develop thin wheel flanges on the leading axle of each truck while the flanges on the trailing axles incur relatively little gauge face wear. This directly affects the frequency and cost of wheel truing and ultimately wheel replacement.

• From a civil engineering perspective, stub-end terminals are less costly compared with the loops because, as noted above, of the land costs and other local space restrictions. Trackwork costs for a stub-end terminal versus a loop could be similar or greater depending on the configuration and amount of special trackwork associated with any terminal station, passing tracks, or storage tracks. Train control system costs are nearly certain to be greater for a stub-end terminal than for a loop terminal.

• Stub-end terminals have construction and maintenance costs associated with special trackwork and train control systems that differ from those of loop tracks. The designer must evaluate options based on life cycle costs.

• Dwell times for a loop terminal are appreciably less than those for a stub-end terminal, which can be advantageous at terminals with extremely close operating headways.

• If double-end cars are selected, it is still possible to have loops at some terminals should local conditions make that choice advantageous.

• Loop tracks are more likely to be sources of noise than stub-end terminals, possibly impacting both the wayside community and patrons alike. The crossover track movements associated with a stub-end terminal are more likely to be a source of groundborne vibration, particularly if a double or “scissors” crossover is used.

• Loop tracks at an intermediate turnback point will require a crossing diamond, which is more likely to be a source of noise and vibration than the ordinary frogs in the crossover tracks associated with a center pocket track.

• If there is a reasonable probability that a line might be extended beyond some initial terminal location, a stub-end track arrangement—and hence double-ended vehicles— would usually be the logical choice.

• Stub-end tracks provide greater flexibility for vehicle storage during off-peak hours.

EGYPTIAN CREATION MYTHS (2 of 2)

Heart and tongue in Egyptian thinking : The heart and tongue represent thought and speech, the attributes of the creator, and are deified as Horus and Thoth (The Moon-God of Egypt).

By his thought and speech Ptah does the following:

• Brings the gods into existence,
• Brings order out of chaos;
• Fixes the destinies (like Marduk);
• Provides food for mankind,
• Divides Egypt into provinces and cities;
• Assigns their places to the various local gods.

(In those days thinking and feeling were associated with the heart, and a simple utterance by the supreme being was thought to be sufficient for the materialization of that thought at that moment. This heart and tongue issue could be found also in the next belief system.

Now hold tight!: This description of Ptah's creative activities closes with the words "..And so Ptah rested (or was satisfied), after he had made everything". Does it sound familiar? Yes! The identification of Ptah with Atum-Re constitutes the link between the Heliopolitan myth of Re as creator and the Memphite Theology which takes the myth as the basis for cosmological speculation of great subtlety.

How about the creation of man? Well it has no special place in Egyptian mythology. There are representations of god Khnum fashioning mankind on the potter's wheel and there are various references in Egyptian texts to this special creative activity, but the line between man and the gods is not as sharply drawn as it is in the next religion. As a result the creation of man has a comparatively slight emphasis in Egyptian mythology.

LIGHT RAIL VEHICLE DESIGN CHARACTERISTICS - Unidirectional/Bi-Directional (1 of 2)

Light rail vehicles are built in a variety of designs and dimensions. In almost all cases, they are capable of being operated in coupled trains. Modern LRVs are generally much larger and heavier than their streetcar predecessors and can have axle loads just as large as, or even larger than, so-called "heavy rail" transit vehicles.

Light rail vehicles vary in the following design characteristics:

1. Unidirectional versus bi-directional
2. Non-articulated versus articulated and, for the latter, the location(s) and configuration of the articulation joints
3. 100% high-floor versus partial low-floor (typically 70% or less) versus 100% low-floor
4. Overall size (width, length, and height)
5. Truck and axle positions
6. Weight and weight distribution
7. Suspension characteristics
8. Performance (acceleration, speed, and braking)
9. Wheel diameter and wheel contour
10. Wheel gauge

These characteristics must be considered in the design of both the vehicle and the track structure.

1. Unidirectional/Bi-Directional
Nearly all of the legacy streetcar systems in North America that survived up through the 1960s used unidirectional vehicles, most often the Presidents Conference Committee (PCC) streetcar. Such “single-end” cars had operator’s controls in the forward end, doors on the right side, and a single trolley pole current collector at the rear. At the end of the line, cars negotiated a turning loop and ran to the opposite terminal. Because these vehicles could negotiate curves with centerline radii as small as 35 feet [10.7 meters], the amount of real estate needed for a turning loop was relatively small, usually only a single urban building lot. Transit companies typically found that the expense of buying properties and building loops was small compared to the savings associated with not having to maintain duplicate sets of control equipment in “double-end” trolley cars.

Current designs of high-capacity light rail vehicles have much larger minimum radius limitations and the amount of real estate that is required to construct a turning loop is much greater. Accordingly, while a few European light rail lines continue to use single-end, single-sided vehicles that require turning loops, most contemporary LRVs have control cabs in both ends and doors on both sides. These cars can advantageously reverse direction anywhere that a suitable crossover track or pocket track can be provided. This arrangement is usually more economical than the turning loop in terms of real estate required and has become the norm for most modern light rail transit systems. Crossovers and pocket track arrangements can often be sited within the confines of an ordinary double-track right-of-way and do not require the supplemental property acquisition needed for turning loops.

EGYPTIAN CREATION MYTHS (1 of 2)

Egyptian belief system is fluid and the creation myth assumes many forms. Underneath them lies the basic experience of the Sun's action upon the slime left by the receding waters of the Nile flood.. The earliest form of the myth, modified later by the theologies of Heliopolis and Memphis, presents the sun-god Atum-Re, seated upon the primeval hillock, and bringing into existence 'the gods who are in his following'. But Atum himself is depicted as rising out of Nun, the primeval ocean (This sounds familiar! Someone must have done some stealing).

In the form of the myth which belonged to Hermopolis, in Middle Egypt, the emergence of Atum was due to the activity of the Ogdoad (These were conceived of as animal forms, four snakes and four dogs, representing primeval chaos. Their names were Nun and his consort Naunet, Kuk and Kauket, Huh and Hauhet and lastly Amon and Amaunet). Atum, emerging from the waters, brings the elements of chaos into order, so that they appear in the texts as gods functioning in their proper places.

In an early form of the myth, according to the Pyramid Texts, Atum is represented as fertilizing himself and producing Shu (air) and Tefnut (moisture); from the union of this pair came Geb (earth-god) and Nut (sky-goddess); here the Heliopolitan theology introduced the figures of the Osirian group, and made Geb and Nut give birth to Osiris and Isis, side by side with Seth and Nephthys, thus completing the Heliopolitan Ennead.

There is another form of the myth arising from the desire of Memphis to vindicate its importance as the new capital of the first dynasties of Egypt. Ptah was the local god of Memphis. The Memphite Theology, as the document which contains this form of the myth is usually called, has transformed the Heliopolitan Ennead by giving the primacy in the activity of creation to Ptah.

In the part of the Memphite Theology which concerns creation, Ptah is equated with Nun, the primeval ocean, and is presented as bringing Atum and all the gods of the Heliopolitan Ennead into existence by his divine word (Here it is again! The power of the word). What might be called the creed of the Memphite Theology is briefly summarized in the following passage of the text:

• "Ptah who is upon the Great Throne
• Ptah-Nun, the father who begot Atum;
• Ptah-Naunet, the mother who bore Atum;
• Ptah the Great, that is, the heart and tongue of the Ennead
• (Ptah) who gave birth to the gods."

Vehicle/Trackway Interface (2 of 2)

It is essential that the track designer, the vehicle designer, and the designers of systems such as signals, catenary, etc., coordinate and cooperate to achieve compatibility between the LRT system components under all operating conditions. These interactions can be facilitated by generating a comprehensive design criteria manual for any new LRT system and keeping it updated with ”as-built” information as the project is developed, constructed, and operated.

It is generally inadvisable to design a new light rail line around the characteristics of only one make and model of light rail vehicle since doing so may limit choices for subsequent vehicle procurements as the system expands and matures. A transit system guideway may remain unchanged for a century or more, during which time it would not be unusual for three or more cycles of vehicle procurements to occur. Instead, it is recommended to consider a universe of candidate LRVs from several manufacturers and develop a fictitious “composite” LRV that incorporates the most restrictive characteristics of several cars, e.g., the longest, the widest, the one with the largest minimum radius capability, etc.

In this fashion, the transit agency will not be forever restricted to using only one particular make and model of LRV. It also minimizes situations where parts of the track alignment are at the absolute minimum or maximum capabilities of the vehicle, a condition that is highly discouraged in any event.

When new vehicles are procured for an existing transit line, the vehicle must be specified to operate on the existing track unless a concurrent rehabilitation and upgrading of the old guideway is proposed. When an existing transit line is extended, the track standards for the extension must accommodate both the old rolling stock and any new vehicles that might be procured.

THE OSIRIAN MYTHS

The myth is about the conflict between Osiris and his brother Seth. The political element of this conflict reflects the course of struggle, which ultimately made upper and lower Egypt a united monarchy. The agricultural element of the myth shows us that Osiris is a vegetation god. Like the Akkadian Tammuz (Dumuzi of the Sumerians) he is a dying and rising god, dies with the dying vegetation and returns to life with its rebirth.

Osiris is Khent-Amenti, Lord of the underworld. He presides over the tribunal which decides on the fate of the departed souls, and in this aspect he is inseparably connected with the complicated ritual of mummification. The outline of the myth of Osiris is contained in the treatise De Iside by Plutarch. According to this account Osiris was a culture hero who taught the ancient Egyptians the art of agriculture and metal-working.

In the myth, Osiris was the son of Geb, the earth-god, and his sister and wife was the goddess Isis, who ruled over Egypt with him and assisted him in his beneficient activities.

While working from home

Recalculate the Gross Plant Heat Rate and Net Plant Heat Rate for a 10 MW scale CFSPP

Vehicle/Trackway Interface (1 of 2)

As vehicle technology continues to evolve, so does the complexity of the interface between the vehicles and the track. There are few hard and fast rules about the relationships between vehicles and track on light rail transit systems. In spite of this lack of design consistency, there are several key vehicle-to-track and trackway parameters that the track designer must consider during design of light rail systems. These include:

1. Vehicle Weight (both empty and with full passenger load)

2. Clearances

• Required track-to-platform location tolerances to meet ADA requirements

• Required clearance between cars on adjacent tracks considering car dynamics

• Required route clearances (wayside, tunnel, bridge) considering car dynamics

3. Wheel Dimensions

• Wheel diameter, which can be very small in the case of low-floor vehicles and is virtually always smaller than that used on freight railroad equipment. Smaller wheel diameters produce higher contact stresses than larger wheel diameters, with resulting implications regarding rail corrugation and wear on both wheels and rail

• Wheel profile or contour, including the wheel tread width, which must be compatible with the rail section(s) selected, particularly in the case of special trackwork

• Wheel gauge, to ensure compatibility with the track gauge, including tolerances

• Wheel back-to-back gauge that is compatible with flangeway dimensions and special trackwork check gauges

4. Longitudinal Vehicle Forces on the Track

• Maximum acceleration and associated tractive forces

• Maximum/emergency deceleration from a combination of friction brakes, dynamic braking and electromagnetic track brakes, including the automatic application of sand

5. Lateral Vehicle Forces on the Track

• Maximum lateral forces resulting from all speed and curvature combinations

6. Dynamic Vehicle Forces on the Track

• Impact of car and truck natural frequencies

• Impact of wheel flats or damaged wheels

THE MYTHS OF RE, THE SUN-GOD

In Egypt the cult of the sun-god has occupied a far more important place than it did in the ritual and mythology of Sumer and Akkad. Shamash, (The Sun-god of Akkad) was the guardian of justice. But he never became one of the triad of gods, and he was never associated with myths of creation. Re, according to tradition, was the first king of Egypt and as Atum he was the creator of the world. As its name indicates, the city of Heliopolis was the chief centre of the cult of Re, and it was probably there that cult of Osiris and that of the sun-god merged during the Old Kingdom period. The Horus-falcon that is to be seen protecting the head of the pharaoh Khafre on his statue, shows the identification of Horus with Re and the association of the kingship with Re. The mythology of Re and of Osiris have become completely blended. But there are still some elements of the solar mythology which remain distinct from the Osiris myth.

Where the Rails and Wheels Meet the Road

Arguably, the two most important defining elements of trackwork for light rail systems are the construction of track in streets and the interface between the wheel of the light rail vehicles and the rails. Track in streets requires special consideration, especially with regard to the control of stray electrical current that could cause corrosion. These embedded tracks also need to provide a flangeway that is large enough for the wheels but does not pose a hazard to other users of the street.

Light rail vehicle wheels do not necessarily match those used in freight railroad service. Wheel diameters are usually much smaller, and the wheel tread is often much narrower. Light rail wheel flanges are often shorter and have a radically different contour than railroad wheels. These variations require special care in track design, especially in the design of special trackwork such as switches and frogs. The compatibility of the vehicle and track designs is a central issue in the development of a light rail system if both components are to perform to acceptable standards.

While light rail may need to share right-of-way (R/W) with pedestrians and vehicles, the designer should create an exclusive R/W for light rail tracks wherever possible. This will make operation more reliable and maintenance less expensive.

TABOO

Taboo is a prohibition, a ban. Taboo has the meaning of an 'unapproachable thing.' Taboo corresponds to the 'divine-heavenly fear' of our time, the breaking of which in many ways will be like committing a 'sin' nowadays. The restrictions are not tied to a divine command and described as 'the oldest unwritten laws of humanity.' When taboo was in full force there was neither the idea of a supreme being in its present context, nor a belief system. Therefore taboo like totem could be said to be older than the supreme being.

The most ancient punishment systems of humanity could be tied to taboo. Avoidance of the dangers that are created by the violation of a taboo may be possible by penance and purification. In other words, by paying something, by refraining from certain things and by cleansing yourself (Can you detect the beginnings of the concepts of expiation, ablution, abstinence and fasting?).

The primitive communities were subjected to a series of prohibitions. They didn't know why. They didn't think of asking questions.

Taboo was accepted as if it is an open truth and the violation of it is believed to be punished automatically (Echoes of the accepted attitudes today?)

Taboos do not co-exist with individualism and the personal freedoms, which should be eradicated. (Precursors of the belief systems?).

Prohibitions are kept alive by an inner necessity; they are connected to the danger of contamination from the banned object; and necessitate ceremonial acts (like the belief systems of today).

All the taboos were ancient prohibitions, imposed externally and by force.

The oldest and most important taboo prohibitions are the two basic laws of totemism: 'Don't kill the totem animal' (it could be extended to the 'kin' as well) and 'avoid sexual relations with the opposite sex of the same clan.'

The primitive people who were living long before the imposition of laws by the gods had this command or the moral rule: You should not kill. This is a rule the violation of which shouldn't go unpunished. The isolation of professional executioners for a set period or temporarily originates from this superstition. The appeasement ceremonies, sacrifices, restrictions, isolation period, atonement and purification ceremonies in the belief systems and also following a battle in primitive communities all originate from one superstition: Thou shalt not kill! This must be familiar.

The individual is asked to sacrifice his/her instinctual satisfactions to the supreme being, who has declared: 'I'll take your revenge.' This is important because in the development of the early belief systems we could see that many things which were relinquished by humanity (because they were 'sins') were turned over to the 'supreme being' and became permissible in his name. This gave earthlings the opportunity to save themselves from the domination of their evil and socially harmful instincts.

Atonement in taboo ceremonies is much more fundamental than purification.

Taboo aims at the most powerful expectations and desires and it is also the typical method of legislation imposed by the chiefs and priests whose purpose is to preserve their assets and privileges.