Classical procedures for selleck chem inhibitor control measurements treat the span and the elevation difference separately. The span is controlled using the orthogonal method and the elevation difference using geometric levelling [2]. There are two main disadvantages in the conventional approach. Firstly, two theodolite stations need to be established in the directions of the rails and secondly, horizontal and vertical measurements are carried out separately. In addition, the longitudinal (stationary) position of the control points is not determined. The classical approach is time consuming and does not ensure redundant measurements.Some alternative methods provided for specific tasks have been published. Kyrinovi? and Kop��?ik in [3] describe a dynamic measurement method with a special mechanism for the accurate definition of the rail shape.
A Leica 360�� prism, attached on a special holder, was used. The position accuracy is low due to the dynamic measurements. A method that would assure better position accuracy and precision requires the establishment of a geodetic network [4]. The procedure is expensive, time consuming and the achieved precision is even lower than that obtained using the proposed approach. Advanced methods tend to the complete automation of measurement process. They are based on specially developed equipment and offer real time measurement results [5].The proposed approach provides simultaneous determination of horizontal and vertical positions of rails from a single instrument station. It is based on the polar surveying method. A precise total station is used along with a special L-shaped platform.
Two precise measuring prisms are attached to the platform. We place the platform on the rail at the desired profile points.The measured polar coordinates are transformed into the Cartesian coordinate system, while the coordinate system is chosen in such a way as to be aligned with the rails. The local Cartesian right-handed coordinate system is used. The obtained coordinates represent a relative relation between the rails.The proposed approach is better than the classical methods due to its cability for faster measurement of profile points. Higher density of points can be achieved with no effort. Using redundant measurements the precision of the measurements as well as the precision of the results can be assessed.
The method ensures homogenous position accuracy of point determination in terms of both horizontal and vertical position. Despite the large number of measurements, the proposed method is still faster and more economical than the conventional approach.2. Instrumentation and Surveying MethodThe Drug_discovery national standard for crane rails selleck products from the Eurocode 3 standards [1] requires the monitoring of:The span between rails;The elevation difference between rails in each profile.The actual span can deviate from the projected one by a maximum of 10 mm.