نتایج جستجو برای: and underground railways
تعداد نتایج: 16831727 فیلتر نتایج به سال:
in the present paper, challenges and prospects of the european railways, along with a proposal for a new strategy policy and specific measures are presented. the declining course of european railways concerning traffic and revenues is first analyzed. conditions to introduce intra - modal competition are surveyed, among them separation of infrastructure from operation as it has been applied in a...
ballast as a part of the railway system plays an important role in the operation of the railways and also has a great impact on repair and maintenance activities. hence most of the repair and maintenance activities in traditional railway systems are due to the defections in the ballast layer and therefore most of the maintenance budget is spent on repairing these defects. these repair and maint...
STUDY OBJECTIVES To locate geographical sources of engine exhaust emissions in Great Britain and to link them with the birth addresses of children dying from cancer. To estimate the cancer initiating roles of nearby roads and railways and to measure effective ranges. DESIGN Birth and death addresses of all children born between 1955 and 1980 in Great Britain, and dying from leukaemia or other...
background: during recent years, overpopulation, increase of wastewater, and drop in water tables has led to high concentration of salts in underground water, which is an important environmental pollutant. if concentration of salt in drinking water exceeds the limits, it will be dangerous for health. the aim of this study was to measure physical and chemical parameters in drinking water of rura...
The study of various countries rail transportation indicators is an appropriate criterion for evaluating the existing performance of Iranian railways. The experiences of other countries can be used to improve the efficiency of Iran’s rail transportation. At the beginning of the study, in order to compare the Iranian railway performance with railways of other countries, various efficiency indica...
Abstract Since the mid-twentieth century, Polish rail network has been experiencing a systematic decline of its lines and this includes railway serving only freight services. One most striking examples transport is sand railways in southern Poland. This world-unique system for transporting backfill used hard coal mining was one spectacular types specialized transport. The general crisis Poland,...
introruction khawf in(iran)-herat and mazaresharif and shirkhan bandar in (afghanistan)-dushanbe in (tajikistan)_(kirgizstan)-kashghar in(china) project railway network is under construction that it is as a significant corridor for revitalizing silk road corridor in the region .at the present there are three different gauge in the region central asia with 1,520 mm gauge and turkey-islamic repu...
Railways were originally uniquely identified with the material of their initial construction and now are technically identified by the characteristic contact of ‘steel wheel on steel rail’. Over 160 years ago failures of iron railway axles led to research into what we now know as metal fatigue. Accidents throughout the ages have acted as catalysts for research and improvements: this lecture wil...
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