الفهرس 
الملخص العربي
The problem statementOnly 14 pages are availabe for public view
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Abstract
Among the various causes that influence the efficiency of the railway, track geometry is perhaps the most important one. It is the forcing function that directly determines response of a free rolling vehicle. Under normal usage, railroad curves lose their smooth alignment, feading to poor ride quality, increased rail wear, accelerated track structure deterioration and higher probability of derailments. Not only the geometry of the track in the horizontal plan is changed but also the elevations of the rails. For the construction and the maintenance of railway tracks, surveying and track alignment procedures are required to monitor the track position and reconstruct the theoretical track position at any time. The methods used for geometry measuring have some shortcoming like the high cost and the need to close the track during the measuring in case of using the measuring carer the need to construct a network of control points along the railway track to be used as a reference station when using the GPS system or time consuming due to separate measurements of the elevations from the horizontal position in case of using the optical chord method.
The present research work aims are developing an instrument and a measuring and a measuring procedure of the three dimendsional position of the track, a new surveying instrument and a new measuring technique are proposed to measure the deviations in the track geometry and the rail’s elevations. The new instrument insures precise measurements and low cost it reduces the measuring time by measuring the elevations in the same time the geometry and insures the flexibility and the automation of the measuring procedure.
Three prototypes have been produced in a continuous modification of the new instrument to achieve the required tasks. Several field measurements were performed to verify the theoretical assessment of the expected accuracy of the new instrument and the new technique.
The results show that the new instrument is precise in measuring the three dimensional posiotion of the track compared with the conventional optical chord method with no need to retrain the measuring group.