ANALYSIS OF RESULTS OF MONITORING AND PREDICTION OF QUALITY DEVELOPMENT OF BALLASTED AND BALLASTLESS TRACK SUPERSTRUCTURE AND ITS TRANSITION AREAS ANALYSIS OF RESULTS OF MONITORING AND PREDICTION OF QUALITY DEVELOPMENT OF BALLASTED AND BALLASTLESS TRACK SUPERSTRUCTURE AND ITS TRANSITION AREAS

Securing durability of parameter quality of track alignment design and track geometry is a goal of each railway infrastructure manager. To accomplish this goal, various methods and procedures are applied, but they are all based on regular diagnostics, analysis of its results according to valid legislation and design and implementation of respective maintenance and repair works. The technological and economic optimization of planning and implementation of maintenance and repair works, based on prediction of quality development of railway track, is conditioned by precisely implemented and evaluated monitoring. In relation to these facts, the first part of the paper brings an overview of the problem of monitoring the ballastless structure and its transition areas around portals of the Turecky vrch tunnel by methods of complex diagnostics and quality evaluation of the structure including prediction of the structural quality development. The second part of the paper deals with the analysis of the detected errors of the ballastless track with specific focus on transition areas and on the ballasted track. It also summarizes the possibilities of elimination of these errors in building further sections with ballastless track. Modernization of these sections within modernization of ZSR infrastructure is a topical problem.


Monitoring of the experimental section
The railway track monitoring determines the state of constructions and facilities of railway infrastructure, state of particular structural parts and their functioning, parameters and wear, with regard to tolerances, health, fire and environmental safety, clearances along the track and walking and handling clearance. The operational capability of railway track is verified by inspections and measurements of constructions and facilities of railway infrastructure in prescribed intervals [1].
The diagnostics of the rail route is focused on: • track skeleton structure -parameters of the track geometry of the track and turnout, -structural elements of the track and turnout, • subgrade structure, -entire structure, -rail bed, -substructure, -foundation, • clearances along a line, • catenary (measurement of the contact wire geometry), • bridges and tunnels -inspections, -photogrammetric measurements, -clearances along the track and supporting strength, • moving rail vehicles and detection of their defects (flat wheels, etc.), buildings and utilities. The paper presents the results of diagnostics of track geometry, carried out by the Department of Railway Engineering and Track Management, Faculty of Civil Engineering, University of Zilina since 2012. The diagnostics is performed in the experimental section near the portals of the Turecky vrch tunnel, as shown by Fig. 1. The objective of the diagnostics is to regularly determine and assess the quality of given parameters, monitor continuously the quality development and predict its future development due to optimization of design and implementation of maintenance and repair works.
The experimental section in the area of portals of the Turecky vrch tunnel, its parameters, measuring devices and diagnostics methods, its assessment and partial results were in detail specified in [2] and this monitoring will continue in the future.
The monitored section has a unique superstructure in Slovak Republic: ballasted and ballastless superstructure. Between these two structures there is a transition area, which is the most After transfer to the computer, on the basis of defined parameter limits of track geometry, for each part of the experimental section there were created: the graph of measured parameters of track geometry,  [4, 5 and 6].
The monitoring method used by the measuring device KRAB TM -Light is contact while the measured data is recorded in the on-board computer.

Analysis of results of the experimental section monitoring
The quality of the track geometry of each evaluated section is presented using: • graphs of measured parameters of track geometry, • tables of local errors with an overview of exceeded maximum values (standard tolerances) of measured parameters and • tables of section evaluation which show: -standard tolerances (SDV) and quality marks (QM) of particular geometric quantities -alignment of the track (SK), track gauge (RK), superelevation (PK) and rail top level (VK), -overall quality mark (OQM) which serves for assessment of track geometry in the evaluated section as a whole, -tamping mark (TM), which helps decide whether to deploy a tamping machine. Unlike OQM, it does not consider gauge tolerances (RK). (They are not maintained by tamping machines). -quality number (QN).
The evaluation of section according to quality marks shall be carried out according to the equation: where b and m are numerical constants determined on the basis of the SDV statistics of relevant parameter and speed zone.
The evaluation using the list of local errors and the section evaluation respect conditions stated in [7 and 8], for tracks with track speed from 120 km.h -1 to 160 km.h -1 included (i. e. for speed zone No. 4 /RP 4/). The provisions of the currently valid document [9] have so far not been included in the respective legislation by the railway infrastructure manager. The measured parameters were evaluated using software according to maximum input tolerances for acceptance of works with the use of new material (MSO), or according to operational tolerances and maximum operational tolerances for RP4 (PO1 to PO7).
The particular measurements in the experimental section were carried out as follows: Slovak Republic). In the following measurements -PO3 and PO4 -further quality degradation of the section 1.1 was diagnosed, confirmed by the increased number of local errors (Fig. 2) as well as worsening value (increase) of the overall number of quality (Fig. 7). In November 2014, the railway infrastructure manager carried out repair interventions in the transition areas of the sections 1.

Section evaluation
The quality marks of the alignment of the right rail (after calculation also of the left one) QM SK (Fig. 3) were within MSO, PO1, PO2 and PO3 measurements placed in the interval 2 < QM ≤ The overview of quality development of the track geometry of the monitored section is shown in Figs. 2 -7. The incidence of local errors of measured parameters is stated separately for ballasted track sections, transition areas and for ballastless track sections (Fig. 2).

Local errors
The experimental section monitoring has been carried out since July 2012, with six-month periodicity. The input measurement (MSO) was carried out 2 days before putting the track in operation. Within the input measurement, 40 local errors were recorded, out of them 30 in sections with ballasted track, 9 in sections with ballastless track and 1 local error was diagnosed in the transition area of the section 2.1. After this measurement, the supplier carried out the repair of track geometry and microgeometry of rail heads by grinding in the transition areas and in the sections with gravel superstructure (unfortunatelly, the supplier did not provide the details of repair works). The operational diagnostics has been applied seven times (PO1 to PO7).
In the second operational measurement (PO2), the local errors of the rail top level of the right rail (VP) and the top level of left rail (VL) were for the first time recorded in the transition area of the section 1.1, confirmed by the track geometry car of ZSR (Zeleznice Slovenskej republiky -the Railways of the  The quality marks of rail gauge tolerance QM RK in all the sections and measurements are in the interval of values 0 < QM ≤ 2, which indicates that the state of track geometry is satisfactory (Fig. 4). Higher values of quality marks QM RK in the sections 1.1 and 2.1 result from higher share of ballasted track sections compared to the sections 1.2 and 2.2 with prevailing better quality ballastless track (also securing higher durability of rail position). The values of QM RK obtained by monitoring carried out during operation (measurements PO1 to PO7) present the rail gauge as a parameter with permanently satisfying quality development.
The quality marks of superelevation QM PK are in the interval of values 0 < QM ≤ 2 in all the sections and 2 < QM ≤ 3 in measurements PO2, PO3, PO4 and PO7 in the section 1.1. After repair interventions (after PO4 measurement) the values moved into the interval 0 < QM ≤ 2. The trend of quality increase in this section proven by measurements PO5 and PO6, is indicated as stopped by measurement PO7: the quality mark QM PK is in the interval 2 < QM ≤ 3 (Fig. 5).
The quality mark with the worst development according to the measurements carried out so far seems to be the quality mark of the top level of the right (after calculation also of the left) rail QM VK (Fig. 6).
The errors of the parameter of the top level of rails are the most frequently occurring defects, which is also confirmed by fourth operational measurement (upper limit + 6 mm) and in the second and fourth operational measurement (lower limit -6 mm) for the left rail. The parameter error on the level of exceeded operational tolerance can be confirmed by errors detected by the measuring car of ZSR in individual measurements carried out within regular measurements in compliance with regulations for rail diagnostics. The completed repair of the track geometry in the transition area decreased the tolerance values but the places with limit tolerance values remained the same (contact of transition area with ballastless track and the start of the ballasteless track structure). In the adjacent rail (section 2.1), errors of the parameters VP, VL on the level of exceeded operational tolerance were not recorded, but the manager carried out a repair intervention in the same time in both rails. The repair intervention carried out in the transition area of the rail no. 2 did not improve the values of parameter tolerances in any way, only a displacement of irregularities and places with reached limit values occurred here. This can also be confirmed by the development of quality marks of considered geometric quantity -top level of the right (after calculation also the left) rail (Fig. 6), where, unlike in the rail no.1, the values of quality marks did not significantly improve after repair interventions.
From the point of view of further quality development and subsequent maintenance planning, there was observed a tendency of development of maximum tolerances of both rails (Figs. 10 and 11) with the prediction of reaching the tolerance of the top level of

Development predictions of structural behavior
The development prediction of structural behavior of the structure as a whole is related to transition areas from the ballastless structure to the ballasted structure as these sections are on the basis of long-term observations considered the most problematic ones. The development monitoring was carried out on the basis of data obtained by the complex continuous method by the measuring trolley KRAB TM -Light. The quality marks reaching the highest values since the first measurement are the quality marks of the selected geometric quantity -top level of the right rail. On the basis of measured data, there were prepared graphs of tolerances of top level of the right (Fig. 8) and left ( Fig. 9) rail in the transition area 1.1. The respective transition area (rail 1 of the south portal) is the most problematic one from the point of view of maintenance, error incidence and reached quality marks. However, it is necessary to mention here that after implementation of repair intervention before the fifth operational measurement, there were recorded slightly higher values of quality marks for top level of right rail in the adjacent rail (section 2.1). It is probably related to the lower quality of repair intervention implementation in the rail no. 2. The tolerances of the top level of the right (after calculation also of the left) rail in the transition area of the section 1.1 (Figs. 8 and 9) detect the parameter errors on the level of exceeded operational tolerance defined by values ± 6 mm in the fourth operational measurement for the right rail, or in the third and  (the top level of the rail). With the exception of the parameter RK (rail gauge), all the other monitored parameters of track geometry of the experimental section contribute to the quality number deterioration by their continuous degradation. The described tendency of quality decrease is expected in the further periods of operation of respective sections. The repair will be feasible only by repair interventions of track geometry carried out as soon as possible after the error detection but no later than the nearest inspection of the track state.
With regard to quality number, the sections 1.2 and 2.2 seem to be sections with slightly deteriorated quality which can be explained by the quality change of operated railway track with mixed train operation. Considering the quality development in the previous monitoring period, there is supposed a permanent decrease of construction quality, provided the operation is without any extraordinary operational events. The improvement of structural quality will be carried out by repair of track geometry as a part of the repair work plan.

Acknowledgement
The paper contains partial results of the grant project VEGA 1/0597/14 "Analysis of methods used to measure the unconventional railway track construction from the point of view of accuracy and reliability". the right (left) rail on the level of exceeded operational tolerance. The developmental tendency shows that the absolute value of maximum tolerance of the top level of right rail will reach the level of operational tolerance at the latest in July 2017, the absolute value of the maximum tolerance of top level of left rail will reach the level of operational tolerance probably earlier -at the latest in April 2017, and these levels of exceeded operational tolerances should be detected within the second measuring campaign of the measuring car ZSR (in summer 2017). After detection of these tolerances, the infrastructure manager is supposed to plan and, as soon as possible, also to carry out the repair of track geometry in the respective section.

Conclusion
The structural parts and parameters of track geometry in the time of operation show signs of quality deterioration. Its monitoring and recording in the experimental section has been carried out for five years. At present the measurements confirm the significant quality deterioration in the transition areas of sections 1.1 and 2.1. The implementation of repair intervention after measurement PO4 caused certain improvement, but later there was again recorded further quality number (QN) deterioration -especially by decreasing quality of parameter VK