foundation system of burj al arab


Environmental Compatibility
 While modern railway systems in general are considered to have comparatively low environmental impacts, high speed rail systems require special attention to ecological appraisal. Two case studies are presented - the new rail lines of the West German Federal Railways, and the European high speed rail project Paris-Brussels-Cologne/Amsterdam — which show that environmental compatibility can be costly and time-consuming. However, it would seem that the environment would not be a main issue for the proposed Amsterdam-Groningen-Hamburg connection if it primarily used existing rail lines.
Relevance of high speed train systems with regard to environmental policy
In general, the railway, as compared to its competitors ( in particular, road and air transport) is a mode of transport with a relatively low environmental impact. 
Among the advantages of modern railway systems are:

  • Their comparatively low space requirement,
  • Their use of electric traction ( which involves no exhaust gas emissions),

  • Their high level of traffic safety,

  • Their comparatively low energy consumption.

According to the German Federal Railway (DB), the average land acquisition per kilometer of route for the two new lines Hannover-Wurzburg and Mannheim-Stuttgart amounts to about one third of that for capacity equivalent motorways.
 Notwithstanding the emissions of the power stations supplying electricity for traction, modern railway technology cause considerably less air pollution than motor traffic.
 The level of traffic safety of the rail system, in terms of the rate of casualties per million passenger kilometers, is about the same as air transport, but compared to road traffic, is between 20 and 30 times more favorable (according to a study of Progons AG).
 Finally, the DB estimates the energy consumption of modern rail transport units per passenger at about one third of motor traffic and one third of motor traffic and one fifth of the of air traffic.
 Although these aspects are favorable regarding the environmental impacts of new rail systems, the planning and construction of such projects meet with considerable public resistance. The reasons are complex.
 The specifications require a sound level of 90 dBA or less at 100 meters from the track centerline at 150 mph, and 75 dBA or less at 5 meters from the track centerline when stationary with all cooling fans and auxiliary equipment operating simultaneously.
 Energy Consumption
 High speed trains are similar in energy efficiency to aircraft. Environmental impact of high-speed rail lists liters/seat as equivalent for planes and high speed trains. The source of energy may result in less carbon dioxide emissions; however this depends on each implementation's actual usage patterns and their indirect effects. Short -haul energy requirements for transporting people are generally more competitive on trains than long haul. (Where rail competes best on time), because takeoff and landing have proportionately high energy requirements per km versus cruising. Also since it uses less energy it emits less carbon. 


From the point of view of required traffic control systems and infrastructure, high-speed rail has the added advantage of being much simpler to control due to its predictable course, even at very high passenger loads; this issue is becoming more relevant as air traffic reaches its safe limit in busy airspaces over London, New York, and other large centers. However, it must be noted that high speed rail systems eliminate the possibility of traffic collisions with automobiles (adding cost, simplicity, and safety), while other systems do not.

An increase in train speed from 140 to 180 km/h led to an increase of about ten times in the generated ground vibrations. If the train speeds increase further and approach the track critical velocity, then the rail deflection due to the applied wheel loads may become much larger. The possible very large rail deflections around this speed may even result in train derailment, thus representing a serious problem for train passenger safety. From the point of view of generation of ground vibrations out side the track, these large rail deflections can be responsible for an additional growth of ground vibration amplitudes.
 Weathering Influences
 The countries studied have different climate conditions that make it hard to come to a general conclusion concerning the worst weather condition for rolling stock. The combinations of snow, temperature, wind etc make the conditions differ from one region to another. During a run a train may be subject to varying climate conditions, from coldness and dry snow to temperatures above zero centigrade.
 The track and the overhead catenary system are affected differently by the various weather conditions. Furthermore, the various rolling stock designs react different to the various kinds of weather and are in some situations more sensitive than others. 
 Attractive Trip Times
This transportation system is versatile and suitable for large distances. For fast movement, effective cost and attractive trip time the high-speed rail lines will attract 68 million travelers yearly.
HSR will significantly reduce travel-related accidents, injuries and deaths which may also reasons for attraction. With increasing demand for regional travel causing airline delays and highway backups, the cost of travel in terms of both time & money has begun to raise concerns within the public & private sectors.
 Travel Speed
 Modern high speed railroad road generally run at speeds of up to 300 km/h (185 mph) on specially designed and built routes.


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