## 5 Continuous Monitoring and Analysis of Track Geometry Quality in Transition Zones  
The main task of VEGA research [13] at the Department of Railway Engineering is to monitor the behavior of the spatial geometric position of the track axes on several experimental sections on the main railway corridor Bratislava-Zilina-Kosice in the Slovak Republic (within the European Corridor _Va_). The first sections of TZ are located within the construction of the double-track tunnel \"Turecky Vrch\" in Trencianske Bohuslavice city in Figures 2b and 5b (measurements 2012-2022), and the second experimental area is located on the construction of a double-track railway bridge in Trencin in Figure 6b (measurements 2017-2022). The purpose of monitoring is to measure the spatial geometric position of the track axes, immediately after the incorporation of building elements into the transition zones. Experimental measurements of these transit zones were performed continuously by a KRAB measuring trolley [17] with a step of 250 mm with wavebands \(\lambda\) = 1 \(\div\) 25 m in Figure 9 within a complete section of the track. Operating deviations of geometric quantities in the evaluation of measurement results are defined in three stages; \(V\) = 160 km/h are shown in Table 2 [18]:  
* degree AL--Alert Limit: if the value is exceeded, it is necessary to assess the detected change and plan future adjustments,
* degree IL--Intervention Limit (Corrections): if the value is exceeded, maintenance works are performed,
* degree IAL--Immediate Action Limit: measures need to be taken to ensure that the risk is reduced to an acceptable level. Figure 8: Time dependence of height changes of TZ, towards “Zilina”: Track axis no. 2. Figure 9: Monitoring the quality of track geometry—by KRAB trolley measurements [13]: (**a**) Principle of continuous measurements of height changes LHD; (**b**) Photo [[PERSON]]. The paper presents the results of monitoring the course of heights behavior in track axes in transition zones (longitudinal height deviations--LHD) in our experiment for speed on railway corridors in the Slovak Republic \(V\) = 160 km/h. Other monitoring parameters (track gauge--TG, rail deformation--RD, track direction--TD, and track cant of rails--TC) were also monitored by the KRAB measuring trolley according to the [18] standard but are not the subject of this text. During the measuring run, the following so-called primary track values are [17]:  
* gauge (potentiometer transducer on the left wheel),
* alignment (lateral versine) of the right rail,
* top (vertical versine) of the right rail,
* cant (new, high reliable, and precise inclinometer),
* track gradient (option),
* track distance (odometer-optical encoder),
* measuring speed. The following items of geometry inspection were available:  
* actual alignment and level in wavebands \(\lambda\) = 1 \(\div\) 25 m,
* separation of all geometric signals into long wave (\(\lambda\) > 25 m) and short wave (\(\lambda\) < 25 m) parts,
* so-called section evaluation--statistic evaluation of the track geometry based on standard deviation and quality index,
* table of local defects, print out of geometrical lay, and tables. At the end of the evaluation of the measurements [13], we can state that the transition zones, using the proposed building elements, represent an increase in the quality and sustainability of the spatial geometry of the track, which is proven by Figures 10 and 11. TZ objects are built in places where it is necessary to reduce the effects of the shock wave, which is caused by trains running in contact with fixed obstacles (fixed track, bridge, tunnel, culvert, etc.). The results of measurements in the experimental track sections show that the stability of the geometric position is ensured (in our case the vertical alignment). According to the results of the inspection, it is proven that all the parameters of the limit deviations in Table 2 were met (for a multi-year period).