Railroad Turnouts - From Surveying to Information System

The information registration of their position in the railway lay-out is necessary. In our case we will point out the design of the information system which could be employed in the railway engineering works during the maintenance of the above mentioned objects in operation. This information system was created for the independent railway society which owns the railway yard in its railway system.

Na tento účel bol navrhnutý informačný systém, ktorý je vypracovaný na stavebné účely a v ktorom sú uložené pôvodné informácie o výhybkách a križovatkách. Základné informácie sú Railroad turnouts and crossings are inseparable elements of railway infrastructure for providing the fluent train traffic which are as a rule, joined into certain trackage groups. The information registration of their position in the railway lay-out is necessary. In our case we will point out the design of the information system which could be employed in the railway engineering works during the maintenance of the above mentioned objects in operation. This information system was created for the independent railway society which owns the railway yard in its railway system.

Introduction
Continuity and safety of the railway transport is closely connected with the fixed built-in construction components of the railroad trackage. The project documentation is to solve their initial design. Various types of the railway yard parts are known requiring specific access during their infrastructure construction. For example, they can be presented by the gridiron at railway stations and companies, the shunting yards, the marshalling yards, etc. where a large number railroad turnouts, crossings, curves, etc are located. The next determinant is train speed along these objects. The higher the speed along turnouts and crossings is, the higher quality of built-in objects is required. This can be ensured by the design and the post cyclic maintenance.
The movement of train carriages causes spatial deformations of these objects (acceleration, braking, lateral strokes, influence of horizontal and vertical forces, density of traffic and other facilities). The objects are changed to a new state which can menace the safety of the running train carriages. The main task is the position and elevation corrections of turnouts, crossings and tracks to the design state. The object should have parameters which are directly determined by their manufacture. In some cases we can speak about the maintenance of the whole railway yard, the parts of the railway yard or the optimisation state for the purpose of the position and elevation minimisation during the cyclic object maintenance.
For this purpose the information system was designed which was finished for construction purposes and in which the original information of the railroad turnouts and crossings is registered.
The basic information is assumed from the design documentation or the optimisation state of the direct measurement in the railway yard or date of the reconstructed railway division.
The main element of this system will be the infrastructure information registration of the turnouts and crossings, curves and direct tracks. The information system ZH-CAD/IS was created on the base of the AUTOCAD product for the particular registered unit, for example the station track yard, the separate railway network of the miscellaneous companies. The advantage of this railway company which owns the railway system in its area, is the estate of the necessary information of their railway network (including turnouts and crossings). On the base of this information the trackage can be maintained according to the design state.

Geodetic survey in the railway yard
The first step is to acquire necessary information about particular objects of the railway gridiron. The initial updating of the database is performed on the basis of the design documentation or geodetic surveying. The required information should be represented by a fixed state which would be obligatory for the consecutive cyclic maintenance of the railway yard.
Geodetic measurements are executed for the purpose of acquiring information for the consecutive track optimisation and updating of the information system by data, if there is no object documentation at our disposal. The observed points are the main points of the railway objects as beginnings, midpoints, ends of turnouts, crossings and alike.
We can influence the measurement precision by the choice of the suitable surveying instruments, surveying methods and number of repetitions in the surveying rounds. With regard to the reality of the position measuring of "mm" it is necessary to choose proper equipment. Owing to the acquired experience, we can recommend the electronic universal surveying instruments with the mean error of angles of 0.15 mg , distances of 1 to 2 mm and elevations of 0.7 mm/km.
The building of a high-quality surveying network has to precede the proper detailed measurement to prevent the infiltra-
The result of surveying works presents the lay-out of the actual state which is transformed to the optimal state of the track axes ( fig. 1). In our case the presented type of the layout serves as a main base for the information system turnouts.

Data processing
Information system is elaborated as the ZH-CAD/IS application of the AUTOCAD environment [1] which knows how to assign the information to the drawn objects by the positioning in the total layout ( fig. 1) of the *.DWG drawing. The first step during the technology preparation was to create the *.SLD slides of the individual object groups (types of railroad turnouts and crossings, walls and other objects) which are displayed together with the object data.
The next step during the information system creation is to elaborate the empty *.DCL libraries including the gaps for their filling. The DCL panels of the libraries are created by VisualLISP of the AUTOCAD (fig. 2). The main base of this information system is the elaborated DWG layout which originated from the base of the design documentation or surveying in the trackage.
Ako príklad uvádzame úpravu objektu v koľajisku zhlavia do projektovanej polohy (obr. 3), ktorý znázorňuje priečne a pozdĺžne After the choice of the certain structure, information about objects is searched from the layout, for example coordinates and elevations of the main object points which is compared with the values obtained by geodetic surveys. During the simplified control of the railroad objects, we can use the distances from the object axes to the track reference points (ZZK) for the purpose of the correct positioning of the track axes and the axes in front of the object (previous turnout or crossing).

Utilisation in practice
We can see a really practical utilisation of this information system for the chosen company or enterprise which owns the railroad network for the support of their traffic capacity.
shows the lateral and longitudinal shifts of the main points of the turnouts parts during the adjustment of the objects into the basic shape and the observance of the railway track axes distances (detailed plan is shown in fig. 1). The cyclic tamping works and train running were the cause of the deformation changes, in our case we can speak of undermined area and the deformations are to 150 mm. We cannot forget the surrounding adjoined objects which are included in the trackage, because the structure of turnouts and crossings can be influenced by the curve deformations in front of or behind the objects. It is necessary to renovate the whole object group at once.
It is necessary to execute the track deformation adjustment not only horizontally and vertically in direct sections and curves, but also by adding or shortening the distances of the presented sections in front of and behind the objects. The elevation adjustment is processed in an independent plan.
The turnouts were adjusted as a whole unit in which we considered the lateral shifts of the turnout axes as determined shifts. The longitudinal shifts along the track axes have their influence on the adherence of the central angles of particular turnouts.
We will present some reasons due to which the renewal of the object position and elevation and the adjustment of their geometric parameters is necessary: -the undesirable running of the trains along the objects, the abrasion of the structure parts, -the distances of the track axes according to the fixed barriers (masts, bridges, abutment and retaining walls, etc.), -the modification of the object parameters to the original state (design state, production parameters, branching angle, distances, etc.). A surveyor carries out measurements of the present position of main points (railroad turnouts, crossings, curves, etc.). If it is necessary to eliminate horizontal and vertical deformations so he designs the adjustment of the objects position and elevation in cooperation with a designer. During the surveying we recommend the referencing of the position and elevation of the main object points to the reference poles or witness track marks ( fig. 2).